Abstract: The present embodiments relate generally to power controllers, and more particularly to synthetic current hysteretic control of a buck-boost DC-DC controller. In one or more embodiments, a controller includes PFM-PWM and Buck-Boost transitions with minimal circuitry and power consumption. In these and other embodiments, the controller includes a low-Iq synthetic ripple generator for use in implementing hysteretic control of a buck-boost controller.

Abstract: A driving circuit and method for buck-boost converter with bootstrap voltage refresh. The driving circuit includes a first bootstrap capacitor provided a first bootstrap voltage to drive the corresponding switch, and a second bootstrap capacitor provided a second bootstrap voltage to drive the corresponding switch. When converter operates in buck mode and the first or second bootstrap voltage is smaller than a threshold, the driving circuit generates current signals to respectively charge the first and second bootstrap capacitors based on an input voltage, and the first and second bootstrap voltages. When converter operates in boost mode and the first or second bootstrap voltage is smaller than the threshold, the driving circuit generates current signals to respectively charge the first and second bootstrap capacitors based on an output voltage, and the first and second bootstrap voltages.

Abstract: Disclosed herein is a switching regulator with a soft start circuit for suppressing an in-rush current. The switching regulator includes a peak detector configured to receive a clock signal and detect a peak voltage of the clock signal, a comparator configured to generate a soft start signal for controlling a soft start of the switching regulator based on a result of comparing a level of the peak voltage of the clock signal to a preset reference voltage level, a counter configured to switch a state of the soft start signal at a time point when a preset soft start time arrives, and a ramp voltage generation unit configured to generate a ramp voltage by adjusting a resistance of a variable resistor based on the soft start signal.

Abstract: A driving apparatus for a voice coil motor includes a signal generator configured to generate a path signal determining a path of a driving current provided to the voice coil motor and a current signal determining a level of the driving current, a controller configured to generate a control signal by comparing a reference current determined by the current signal, with the driving current flowing in the voice coil motor, and a driving circuit unit including transistors connected to the voice coil motor, the transistors being configured to form the path of the driving current by performing a switching operation based on the path signal and the control signal.

Abstract: A control system for a DC-DC voltage converter includes a microcontroller having first and second applications. The first application commands the microcontroller to generate a first signal that is received at a first pin on a high side integrated circuit to transition a first plurality of FET switches to an open operational state, and that is received at a first pin on the low side integrated circuit to transition a second plurality of FET switches to the open operational state. The second application commands the microcontroller to generate a second signal that is received at a second pin on the high side integrated circuit to transition the first plurality of FET switches to the open operational state, and that is received at a second pin on the low side integrated circuit to transition the second plurality of FET switches to the open operational state.

Abstract: A wireless power transmission device comprises a power transmitter and a power receiver. The power transmitter is adapted to convert an input DC power into an electromagnetic energy. The power transmitter includes a wave generating circuit adapted to generate a square wave control signal having a predetermined frequency and a predetermined duty cycle according to the input DC power, a switching control drive circuit configured to convert the input DC power into an alternating electrical signal according to the received square wave control signal, and a first coil coupling circuit configured to convert the alternating electrical signal from the switching control drive circuit into the electromagnetic energy and output the electromagnetic energy. The power receiver is electromagnetically coupled with the power transmitter and adapted to receive the electromagnetic energy from the power transmitter.

Abstract: Embodiments of ripple generation devices for a constant on-time voltage regulator and methods for ripple generation for a constant on-time voltage regulator are described. In one embodiment, a ripple generation device for a constant on-time voltage regulator includes a ripple generator configured to generate a ripple signal, a detector operably connected to the ripple generator and configured to detect a difference between an amplitude of the ripple signal and at least one reference amplitude and a feedback controller operably connected to the ripple generator and the detector and configured to generate a control signal for controlling the amplitude of the ripple signal based on the detected difference. Other embodiments are also described.

Abstract: A DALI interface circuit with bootstrap function, the DALI interface circuit is powered by a power supply circuit, and includes a rectification module, a communication transmitting circuit electrically connected to the rectification module, and a signal input terminal electrically connected to the communication transmitting circuit, the communication transmitting circuit has a MOS transistor Q2 and a bootstrap circuit electrically connected to the MOS transistor Q2. The invention simplifies the solution, reduces components, reduces the cost, and saves space on the circuit board. The communication logic has become simpler and more stable.

Abstract: USB controllers, systems and methods are presented to conserve power in a USB controller, in which a transmitter transmits data to a line of a connected USB cable according to a transmit data signal, and a pull down circuit selectively sinks current from a supply node of the transmitter when the transmit data signal is in a first state, refrains from sinking the first current from the supply node when the transmit data signal is in a different second state.

Abstract: A switching regulator includes a clamp circuit which clamps the output voltage of the error amplifier to the clamp voltage when an output voltage of an error amplifier is higher than a clamp voltage, a constant voltage generation circuit having one end connected to an output terminal of the error amplifier, and a phase compensation capacitor having one end connected to the other end of the constant voltage generation circuit, and the other end connected to a ground terminal. When the clamp circuit clamps the output voltage of the error amplifier, the constant voltage generation circuit lowers the voltage at one end of the phase compensation capacitor by a prescribed voltage. When the clamped state of the output voltage of the error amplifier is released, the constant voltage generation circuit lowers the voltage of the output terminal of the error amplifier from the clamp voltage by the prescribed voltage.

Abstract: A control circuit for compensating output loss of a power converter includes a sampling voltage generator, a time-to-voltage converter, and a compensation signal generator. The sampling voltage generator generates a sampling voltage corresponding to a detection voltage according to a first reference current, a second reference current, and the detection voltage. The time-to-voltage converter generates a corresponding voltage according to a period of a gate control signal controlling a power switch of a primary side of the power converter and a discharge time of a secondary side of the power converter. The compensation signal generator generates a compensation signal compensating the output loss according to the sampling voltage and the corresponding voltage.

Abstract: A control circuit for a switching power includes a driver unit that receives an error signal outputted from an error amplifier and generates driving pulses to be applied to a power semiconductor switching device on the basis of the error signal; a short-circuit detection circuit that determines whether a short-circuit occurs between a feedback terminal and a comp terminal of the control circuit; a holding circuit that holds the error signal; and a switching circuit, wherein when the short-circuit detection circuit determines that the short-circuit occurs, the switching circuit provides an error signal held by the holding circuit prior to the detection of the short-circuit to the driver unit instead of the error signal outputted from the error amplifier so that the driver unit does not generate the driving pluses based on the error signal outputted from the error amplifier when the short-circuit is determined to have occurred.

Abstract: A converting apparatus includes: a driving device arranged to charge a connecting terminal by a charging signal and to discharge the connecting terminal by a discharging signal for generating a driving signal; a filtering device coupled to the connecting terminal for generating an output voltage according to the driving signal; and a controlling device coupled to the connecting terminal, for receiving the driving signal to generate a control signal. The driving device is arranged to generate the charging signal and the discharging signal according to the control signal. A method of generating an output voltage includes the steps of generating a driving signal; filtering the driving signal to generate the output voltage; receiving the driving signal to generate a control signal; and generating the charging signal and the discharging signal according to the control signal.

Abstract: A power supply control circuit is connected to and controls a system power supply IC. The system power supply IC has multiple power supply circuits and is capable of outputting multiple power supply voltages. The system power supply IC activates the multiple power supply circuits at one time using a common enable signal. The power supply control circuit includes a gate circuit and a first switch unit. The gate circuit generates the common enable signal based on a control signal and a selection signal. The control signal is output from a control device during a usual operation. The selection signal is a signal that selects one of the multiple power supply circuits which is required to output the power supply voltage. The first switch unit is driven by a power-on signal during system activation, and switches on or off the selection signal input to the gate circuit.

Abstract: A circuit has a variable output that changes an output of a fixed input inversion amplification circuit, which includes a first operation amplifier with one input terminal that is applied with a fixed input value. The circuit includes an intermediate inversion amplification circuit having a second operation amplifier with an output terminal that is connected to another input terminal of the operation amplifier included in the fixed input inversion amplification circuit. One input terminal of the second operation amplifier is applied with the same input value as the fixed input value applied to the one input terminal of the first operation amplifier. Another input terminal of the second operation amplifier is applied with a variable input corresponding to an output of the first operation amplifier.

Abstract: A resonant converter with adaptive switching frequency operates continuously at best efficiency point. A power switch at primary side is turned off when a current flowing through a corresponding output power stage at secondary side falls to zero.

Abstract: Various methods and devices that involve control circuits for power converters are disclosed. One method comprises controlling a switch using a control signal based on a comparison signal. The switch controls a transfer of power between an input node, which receives an input, and an output node. The method comprises measuring an output of the power converter, generating an error signal based on the output, generating a periodic ramp signal with a varying period, providing the error signal to a first input terminal of a comparator, providing the ramp signal to a second input terminal of the comparator, and generating the comparison signal based on the error signal and the ramp signal using the comparator. The method comprises increasing a slope of the ramp signal in response to an increase in the input, and increasing the slope of the ramp signal in response to a decrease in the varying period.

Abstract: A circuit includes a timer circuit configured to generate a first control signal defining a first time period and a second control signal defining a second time period. A controller is configured to control a high-side and a low-side transistor of a half-bridge circuit in response to the first and second control signals only during a first switching cycle of the half-bridge circuit. The half-bridge circuit includes a bootstrap capacitor coupled to a node between the high-side and low-side transistors. The controller turns on the low-side transistor for the first time period during the first switching cycle and configured turns off the low-side and the high-side transistors for the second time period during the first switching cycle.

Abstract: A switching converter comprising a regulation circuit adapted to regulate an output value of the converter based on a ramp signal is provided. A feedback circuit adapted to control at least one of a delay and a slope of the ramp signal based on a parameter of the ramp signal is also provided. A method of regulating an output value of a switching converter is also presented.

Abstract: A control system for a DC-DC voltage converter includes a microcontroller having first and second applications. The first application commands the microcontroller to generate a first signal that is received at a first pin on a high side integrated circuit to transition a first plurality of FET switches to an open operational state, and that is received at a first pin on the low side integrated circuit to transition a second plurality of FET switches to the open operational state. The second application commands the microcontroller to generate a second signal that is received at a second pin on the high side integrated circuit to transition the first plurality of FET switches to the open operational state, and that is received at a second pin on the low side integrated circuit to transition the second plurality of FET switches to the open operational state.

Abstract: An exemplary apparatus provides a regulated DC voltage output from an input from supply DC voltage source. A regulation circuit having an input terminal coupled to the supply DC voltage source, an output terminal on which is provided the regulated DC voltage output, and a current control terminal capable of controlling a maximum current that can flow through the regulation circuit where a level of maximum current is controlled proportionate to an amount of resistance connected to the current control terminal. A surge control circuit connected to the current control terminal automatically supplies a variable resistance beginning with one resistance at turn-ON and varying to another resistance at a predetermined time interval after turn-ON to limit the current that can flow at turn-ON until a steady state of the regulation circuit is reached.

Abstract: Disclosed examples provide DC-DC converters and control circuits to provide high and low-side driver signals and to selectively adjust a delay time between a low-side switching device turning off and a high-side switching device turning on according to a comparator signal, including a clocked comparator circuit referenced to a switching node to sample the voltage across the high-side switching device in response to a first edge of the high-side driver signal, and to generate the comparator signal indicating a polarity of the sampled high-side switch voltage to facilitate zero voltage switching of the high-side switching device.

Abstract: A switch-mode power supply includes a transformer, a power transistor, pulse generation circuitry, and a dual ramp modulation (DRM) circuit. The power transistor is coupled to a primary coil of the transformer. The pulse generation circuitry is configured to generate a power transistor activation signal. The DRM circuit is coupled to the pulse generation circuitry. The DRM circuit is configured to generate a leading edge blank time signal that disables inactivation of the power transistor activation signal for a predetermined interval (a leading edge blank time) after a leading edge of the power transistor activation signal. The DRM circuit is also configured to generate a reset signal that inactivates the power transistor activation signal while the leading edge blank time signal is activated.

Abstract: A voltage regulator for driving a digital circuit includes an input terminal and an output terminal, a pass device and a first capacitor, and a boost circuit connected to the pass device or to the first capacitor and having a regulator boost input terminal connectable to the boost signal output terminal. The output terminal is connectable to a power terminal of a digital or switching circuit having at least a boost signal output terminal. The boost circuit includes a boost capacitor and a switching arrangement connected to the regulator boost input terminal and connected to the boost capacitor. The switching arrangement is controllable by a boost signal generated by the digital or switching circuit.

Abstract: A digital-to-time converter includes: a digital-to-analog converter configured to generate a precharge voltage corresponding to a value of a digital code; a ramp generator configured to precharge a capacitor connected to a first node based on the precharge voltage, and to charge or discharge the capacitor based on a reference current provided from a current source in response to a transition of an input clock signal to generate a ramp voltage in the first node; and a comparator configured to generate an output clock signal based on the ramp voltage, wherein the ramp generator includes: a first switching circuit configured to provide a first current path between a second node connected to the current source and the first node; and a second switching circuit configured to provide a second current path from a power supply voltage source to the second node.

Abstract: A sample and hold circuit takes a sample of the current flowing through an inductor of a buck switched-mode power supply (SMPS) at substantially the middle of the low side portion (50 percent point during low side switch ON) of the pulse width modulation (PWM) period. This sample of the current through the SMPS inductor during the low side ON 50% point may be considered as the “average” or “DC output” current of the SMPS, and taken every time at precisely the same low side ON 50%. A constant current source and sink are used to charge and discharge a timing capacitor whose voltage charge is monitored by a high speed voltage comparator to provide precise sample timing.

Abstract: A switching power converter with a hysteretic current-mode controller switches at a fixed frequency responsive to a pulse generator that pulses a set signal and a reset signal at the fixed frequency. A power switch in the switching power converter is configured to close responsive to the pulsing of the set signal and to open responsive to the pulsing of the reset signal.

Abstract: Disclosed examples include synchronous rectifiers and flyback converters, integrated circuits and operating methods, in which a first switch is turned on to allow current to flow for a first time period in a first direction in a transformer primary winding responsive to a first switch voltage transitioning below a first threshold, and a second switch is turned on for a second time period after the first time period to transfer energy from a secondary transformer winding to drive a load. In the same converter cycle, the second switch is again turned on for a third time period in response to a second switch voltage transitioning below a second threshold at one of a series of troughs of a resonant ringing voltage waveform across the second switch, to cause current flow in a second direction in the primary winding to discharge a capacitance of the first switch to cause the first switch voltage to transition below the first threshold to initiate a subsequent converter cycle.

Abstract: A controller, and related method, configured to generate a duty cycle control signal for controlling an output voltage of a switched mode power supply as a function of a reference signal. In one embodiment, the controller is configured to sample a signal indicative of the output voltage to generate a first sampled signal, filter out a ripple component of the first sampled signal to generate a filtered signal, and generate a feedback control signal based on the filtered signal. The controller is also configured to sample a signal indicative of an input voltage of the switched mode power supply to generate a second sampled signal, generate a feed-forward control signal based on the second sampled signal and a feed-forward reference voltage, and generate the duty cycle control signal based on the feedback control signal and the feed-forward control signal.

Abstract: A pulse generator includes a mode controller that detects a state in which there has been no transition of a pulse signal to the off level for a given cycle (period). When such a state is detected, the pulse generator transits to a skip mode. In the skip mode, the period is repeatedly switched between: (i) a first period in which the pulse signal is maintained at the on level over multiple cycles; and (ii) a second period in which the pulse signal is forcibly switched to the off level so as to charge the bootstrap capacitor by means of a bootstrap circuit.

Abstract: In a controller for a DC to DC converter, PWM signal generating circuitry generates a set of PWM signals phase-shifted relative to one another, and controls states of the PWM signals according to a set of control signals. Each PWM signal of the PWM signals has an on-time state and an off-time state. Ramp signal generating circuitry, coupled to the PWM signal generating circuitry, generates a set of ramp signals having substantially the same ramp slope. Each ramp signal of the ramp signals is generated in response to detecting an on-time state of a corresponding PWM signal of the PWM signals. Additionally, a comparing circuit, coupled to the PWM and ramp signal generating circuitry, alternately compares the ramp signals with a preset reference to generate the control signals. A corresponding control signal of the control signals changes the corresponding PWM signal from the on-time state to an off-time state.

Abstract: Disclosed is a high voltage power system with enable control, comprising a high voltage start-up circuit, a PWM control module, and a driving module; the high voltage start-up circuit comprises a first transistor, a third transistor, a fourth transistor, a resistor, a diode, a VDD detection unit and an I/O interface unit; the high voltage start-up circuit is controlled by an input of a pin EN; when the pin EN is set, the high voltage start-up circuit stops working; the power system is shut off and doesn't restart, and enters a zero standby state; when the pin EN is reset, the high voltage start-up circuit restores to work, and the power system restarts and enters a normal working state. The power system having the high voltage start-up circuit with enable control has characteristics that the standby input power consumption and standby input current are both close to zero.

Abstract: An electronic apparatus includes a converting circuit and a first control circuit. The converting circuit converts an input voltage to an output voltage. The first control circuit compares a feedback signal representing the output voltage with a target voltage to generate an error voltage. When the electronic apparatus is on a starting-up status and the error voltage is not greater than a threshold voltage, the first control circuit outputs a first driving signal to drive the converting circuit according to the error voltage. When the electronic apparatus is on a starting-up status and the error voltage is greater than the threshold voltage, the first control circuit stops outputting the first driving signal. A frequency of the first driving signal is determined according to the error voltage.

Abstract: According to at least one aspect, a circuit for controlling a power converter including an inductor having a terminal coupled to a supply voltage by a switch is provided. The circuit includes a detector configured to detect voltage transient events in an output voltage of the power converter and generate a control signal based on the detected voltage transient events and a control signal generator configured to receive the control signal and control operation of the switch based on the control signal at least in part by varying an on-time of the switch during the voltage transient events and holding the on-time of the switch constant when no transient event is detected by the detector.

Abstract: A power net system for a fuel cell vehicle includes: a diode having a first end connected to an output stage of a fuel cell stack; a fuel cell load device branched and connected between the output stage of the fuel cell stack and the diode; a first relay positioned between the output stage of the fuel cell stack and the fuel cell load device and configured to connect or separate the output stage of the fuel cell stack and the fuel cell load device; and a second relay having a first end connected to a second end of the diode and a second end connected between the first relay and the fuel cell load device.

Abstract: A DC/DC converter in which a both-end voltage of each of capacitors can be safely uniformalized while an over current, which is passed through between the capacitors composing the DC/DC converter, is prevented. In a DC/DC converter which includes a plurality of switching elements, a reactor, a low-voltage side capacitor, a high-voltage side capacitor, a charge-discharge capacitor, and a controller which drives and controls the switching elements, the controller performs soft start control in which a duty ratio of at least one of the switching elements is gradually varied from 0% to 100%, and the switching element, in which the soft start control is not performed during the term of the soft start control, is turned off.

Abstract: A ramp signal generator may include a reference current generation unit suitable for generating a reference current based on a gain; a ramp signal generation unit suitable for generating a ramp signal according to the reference current; a replica current supply unit suitable for supplying a replica current using the reference current generation unit; and an offset compensation unit suitable for compensating for an offset of the ramp signal generated by the ramp signal generation unit using the replica current.

Abstract: Various methods and devices that involve control circuits for power converters are disclosed. One method comprises controlling a switch using a control signal based on a comparison signal. The switch controls a transfer of power between an input node, which receives an input, and an output node. The method comprises measuring an output of the power converter, generating an error signal based on the output, generating a periodic ramp signal with a varying period, providing the error signal to a first input terminal of a comparator, providing the ramp signal to a second input terminal of the comparator, and generating the comparison signal based on the error signal and the ramp signal using the comparator. The method comprises increasing a slope of the ramp signal in response to an increase in the input, and increasing the slope of the ramp signal in response to a decrease in the varying period.

Abstract: A multi-level, step-up converter circuit includes an inductor including one terminal in communication with an input voltage supply. N transistor pairs are connected in series, where N is an integer greater than one. First and second transistors of a first pair of the N transistor pairs are connected together at a node. The node is in communication with another terminal of the inductor. Third and fourth transistors of a second pair of the N transistor pairs are connected to the first and second transistors, respectively. (N?1) capacitors have terminals connected between the N transistor pairs, respectively. An output capacitor has a terminal in communication with at least one transistor of the N transistor pair.

Abstract: Noise introduced in an output signal of a pulse-width modulator (PWM) may be reduced by changing the time duration that a switch is driving the output node. Because the power supplies coupled to the switches are the source of noise in the output signal of the PWM, the time duration that the power supplies are driving the output may be reduced to obtain a subsequent reduction in noise in the output signal. For example, when a small signal is desired to be output by the PWM, the switches may be operated for shorter time durations. Thus, the switches couple the noise sources to ground for a duration of a cycle to reduce contribution of noise to the output. But, when a larger signal is desired to be output by the PWM, the switches may be operated for longer time durations or the conventional time durations described above.

Abstract: A circuit that stabilizes an output signal of a voltage regulator includes a glitch amplifier, a pulse generator, and a transistor. The glitch amplifier amplifies glitches in the output signal and generates a glitch amplifier output signal. The pulse generator receives the glitch amplifier output signal and generates a control signal. When there is a positive glitch in the output signal and a voltage level of the glitch amplifier output signal is less than a first threshold voltage, the pulse generator deactivates the control signal, which turns off the transistor. When there is a negative glitch in the output signal and the voltage level of the glitch amplifier output signal is greater than a second threshold voltage, the pulse generator activates the control signal, which turns on the transistor and provides a compensating current surge to reduce a voltage droop in the output signal.

Abstract: A switching voltage converter using an isolated topology includes a transformer for coupling power from an input source to an output load. The transformer must be protected to prevent saturation of its core due to excessive magnetic flux density as the transformer transfers power from its primary side to its secondary side. The magnetic flux is estimated using a voltage measured on the primary or secondary side of the transformer, wherein the secondary-side voltage may be a rectified voltage. If the estimated magnetic flux is detected as approaching a saturation level of the transformer core, any power being input to the transformer is curtailed. This may be accomplished by modifying pulse-width modulated (PWM) waveforms controlling power switches that control the input power transferred to the transformer. Using these techniques, transformer saturation may be avoided without requiring a significantly oversized transformer within the voltage converter.

Abstract: A sample and hold circuit takes a sample of the current flowing through an inductor of a buck switched-mode power supply (SMPS) at substantially the middle of the low side portion (50 percent point during low side switch ON) of the pulse width modulation (PWM) period. This sample of the current through the SMPS inductor during the low side ON 50% point may be considered as the “average” or “DC output” current of the SMPS, and taken every time at precisely the same low side ON 50%. A constant current source and sink are used to charge and discharge a timing capacitor whose voltage charge is monitored by a high speed voltage comparator to provide precise sample timing.

Abstract: A method for generating a pulse width modulation (PWM) control signal includes generating a sawtooth ramp signal at a first frequency under standard operating conditions using a ramp generator, generating a PWM square wave having a rising edge at a falling edge of the sawtooth ramp signal and a falling edge when the sawtooth ramp signal exceeds an error threshold, adjusting the frequency of the sawtooth ramp in response to a changed operating parameter of the ramp generator, and adjusting a peak input voltage of the ramp generator simultaneous with adjusting the frequency of the sawtooth ramp, thereby preventing one of a voltage overshoot and a voltage undershoot.

Abstract: Single-input-multiple-output (SIMO) DC-DC converters and SIMO DC-DC converter control circuits are disclosed. An example DC-DC converter control circuit includes a switch controller to control respective switches of a SIMO DC-DC voltage converter that has multiple output circuits. The example control circuit also includes an arbitration circuit that determines a first one of the output circuits to have priority over other ones of the output circuits based on a priority signal, and selects a first output circuit to be charged during a first time slot based on the priority signal and based on first kick signals indicating that the at least two output circuits are to be charged. The control circuit also includes a next kick detector that determines a second one of the output circuits to be charged during a second time slot after the first time slot based on the priority.

Abstract: A circuit for activating a capacitive MEMS structure is provided, with the capacitive MEMS structure having an oscillator element and an electrostatic excitation unit with a first input connection and a second input connection. The circuit includes a high voltage generator, a first pump capacitor, a second pump capacitor, a control unit, and a low voltage operation amplifier. The high voltage generator generates a high voltage and connects to the first input connection and the second input connection. The first pump capacitor is connected to the high voltage generator and includes a first connection connected to the first input connection. The second pump capacitor connects to the high voltage generator and includes a first connection connected to the second input connection. The control unit connects to a second connection of the first pump capacitor and a second connection of the second pump capacitor. The low voltage operation amplifier connects to the control unit.

Abstract: The system and method creates a substantially constant output voltage ripple in a buck converter in discontinuous conduction mode by varying the on-time of a pulse width modulator (PWM) signal driving the buck converter when the buck converter is operating in discontinuous conduction mode. A first signal is generated that is a function of the switching frequency of the buck converter. This signal is low-pass filtered and compared with a second signal that is a function of the switching frequency of the buck converter when operating in continuous conduction mode and with constant PWM on-time. The output signal generated by the comparator is a signal that is equal to the ratio of the first signal and the second signal. The on-time of a voltage controlled oscillator is controlled by the output signal, the oscillator signal causing the on-time of the PWM signal to vary in a controlled fashion.

Abstract: A regenerative clamping circuit for a power converter using clamping diodes to transfer charge to a clamping capacitor and a regenerative converter to transfer charge out of the clamping capacitor back to the power supply input connection. The regenerative converter uses a switch connected to the midpoint of a series connected inductor and capacitor. The ends of the inductor and capacitor series are connected across the terminals of the power supply to be in parallel with the power supply.

Abstract: Disclosed are controllable drive circuits for powering an organic light emitting diode (OLED) or other electronic load. According to one implementation, a circuit structure is provided that applies a pulse width modulated (PWM) drive current to an OLED. The time-average drive current to the OLED can be modulated in accordance with a periodically sampled control signal. In turn, the luminance of the OLED can be suitably varied over a control range. Circuit structures provided may be fabricated at least in part on a common substrate such that respective integrated circuit devices are defined. In one or more implementations, at least a portion of drive circuits may be fabricated within a 65 nanometer (or smaller) environment.

Abstract: The various embodiments described herein include systems, methods and/or devices used to produce a rectified and regulated output signal. In one aspect, the method includes, at a circuit, comparing an output signal at an output node with an input signal at an input node, wherein the output signal is a rectified and regulated signal, and the input signal is an unrectified and unregulated signal, and computing a difference between a reference signal and a comparison signal. Power transfer from the input node to the output node is prevented when the output signal is greater than the input signal. Furthermore, power transfer from the input node to the output node is regulated to produce the rectified and regulated output signal when both the input signal is greater than the output signal, and when the magnitude of the reference signal exceeds the magnitude of the comparison signal.