Abstract: Circuit and method for controlling a synchronous rectifier. A circuit for monitoring the drain to source voltage of an SR transistor in a secondary side circuit of a voltage converter is disclosed, having a circuit for generating a gate control circuit for the SR MOSFET; the circuit preventing subsequent gate control signals until a primary turn on detection signal is received. In another embodiment a circuit for generating the primary turn on detection signal is provided. A method for controlling an SR transistor is disclosed comprising monitoring the drain to source voltage of the SR MOSFET, generating a gate control output, and preventing subsequent gate control output signals until a primary turn on detection signal is received. In another method embodiment a method for generating the primary turn on detection signal is disclosed. An SR embodiment incorporating the control circuit embodiments is disclosed.

Abstract: An example disclosed method to handle a reference voltage change in a digital power supply includes receiving a first value associated with a first reference voltage having a first voltage magnitude at a digital signal processor of a digital power supply, comparing the first reference voltage to an output voltage of the digital power supply, controlling the digital power supply based on the comparison between the first reference voltage and the output voltage, receiving a second value associated with a second reference voltage having a second voltage magnitude, determining that the first voltage magnitude is different than the second voltage magnitude, in response to determining that the second voltage magnitude is different than the first voltage magnitude, determining a voltage profile, and controlling the digital power supply based on the voltage profile.

Abstract: A self-oscillating switching regulator includes a control winding N3allowing a voltage to be induced therein by a magnetic flux created in a primary winding N1 of a high frequency transformer T, a capacitor C3 charged by the voltage induced in the control winding N3, a transistor Q2 that is turned off when the voltage across the capacitor C3 reaches a predetermined level, a switching element Q1 driven by the transistor Q2 to switch on or off an input current through the primary winding N1 of the high frequency transformer T, and a control winding adjuster for changing by switching the number of turns of the control winding N3 on the basis of the operating temperature.

Abstract: An automatic power supply converting circuit includes a live input terminal, a neutral input terminal, a relay, a regulator, a voltage divider circuit, an identifying circuit, a switch circuit and a voltage doubling circuit. The live input terminal and the neutral input terminal are configured for receiving a first alternating current (AC) voltage. The regulator is configured for filtering and steadying the first AC voltage and outputting a regulated voltage. The voltage divider circuit is configured for sampling the first AC voltage and outputting a divided voltage. The identifying circuit is configured for comparing a divided voltage with a reference voltage, and outputting a control signal. The switch circuit is configured for controlling the relay to be conductive or not. The voltage doubling circuit is capable of being controlled by the relay and outputting a doubled voltage.

Abstract: An output circuit in accordance with one embodiment of the present invention includes: an input terminal for receiving an input signal; an output transistor connected between a first power supply and an output terminal; a current control circuit connected to the input terminal and the output transistor for controlling current outflow and inflow for the gate of the output transistor based on the input signal; a voltage generating circuit connected to the first power supply; and a switch circuit coupled between the gate of the output transistor and the voltage generating circuit, the switch circuit having alternatively an on state and an off state thereof in response to the input signal; wherein the switch circuit becomes the off state when the potential difference between the gate of the output transistor and the first power supply becomes equal to or below a predetermine value regardless of the voltage level of the input signal.

Abstract: A switching mode power supply (SMPS) and a driving method thereof are provided. The SMPS includes a power supply block that includes a first switch coupled to a first coil of a primary side of a transformer for converting an input voltage, wherein the power supply block supplies power to a second coil and a third coil of a secondary side of the transformer according to operation of the first switch; and a PWM signal generator determines a turn-on time of the first switch according to the input voltage, and the turn-on time is determined regardless of a power magnitude of an output terminal connected to the second coil. Accordingly, screen noise due to a ripple can be eliminated and stress on the switch breakdown due to excessive power input can be reduced to enable an SMPS with stable driving.

Abstract: To provide a power supply apparatus having high control resolution of an output power. A PWM signal generating circuit includes: a non-inverting element 31, and an inverting element 32; and further includes a counter 11 for performing count operation in response to rising of a clock signal, a counter 12 for performing count operation in response to falling of the clock signal, comparison circuits 21, 22, and a multiplexer 20. These circuit elements are controlled by PWM control means 10. As another circuit element, the PWM signal generating circuit includes a logical sum element 33. The PWM signal generating circuit serves to arbitrarily change both period and logic “H” time of a PWM signal to be outputted at a time interval which is one half of the clock period. Thus, there is provided a power supply apparatus in which resolution of a PWM signal has been improved within a broad duty range, and fine control of an output power has been performed within a broad output power range.

Abstract: A load compensation circuit for a switching regulator including a comparator circuit and an adjustable voltage source. The switching regulator includes a switch circuit for converting an input voltage to a regulated output voltage and for driving a load current, and a controlled switch driver circuit having a supply voltage input and an output driving the switch circuit. The comparator circuit senses the load current and adjusts a voltage control signal to adjust switching efficiency based on the load current. The voltage source has an input receiving the voltage control signal and an output for providing a switch supply voltage to the supply voltage input of the switch driver circuit, where the voltage source adjusts the switch supply voltage based on the voltage control signal. A method of compensating a switching regulator based on load including sensing load current and adjusting the switch supply voltage to adjust switching efficiency.

Abstract: Methods and apparatus relating to low power optimized voltage regulators are described. In one embodiment, a voltage regulator controller may cause leakage current from a load to drain a capacitor (e.g., coupled in parallel with the load) during a reduced power state.

Abstract: A switching regulator integrated circuit (IC) is disclosed that includes a switch circuit that further includes a first switch and a second switch, a mode selector circuit controlled by external circuitry to select between a first mode and a second mode, and a control circuit. In response to a feedback signal from the switch circuit, when the first mode is selected, the control circuit toggles the first switch and the second switch ON and OFF alternately at a fixed first frequency. When a second mode is selected, the control circuit causes the second switch to turn OFF completely and the first switch to switch ON and OFF at a variable second frequency.

Abstract: A power converter and method of controlling a power switch therein to improve power conversion efficiency at low output current. In one embodiment, the power converter includes a first power switch coupled to a source of electrical power and a second power switch coupled to the first power switch and to an output terminal of the power converter. The power converter also includes a controller configured to alternately enable conduction of the first and the second power switches with a duty cycle in response to an output characteristic of the power converter. The controller is configured to control a level of current in the first power switch when the second power switch is substantially disabled to conduct.

Abstract: A power supply (V1) for an electrical device comprising a transformer (X1) having primary and secondary windings. The primary winding is connectable to an AC voltage supply and circuitry on the secondary side is arranged to provide a DC output voltage for the electrical device. The power supply also comprises a switch (111—transistors Q1 & Q2) between the primary winding of the transformer and the AC supply, and a rectifier (Diode D6) for rectifying the AC voltage. The switch is arranged to switch on at some point as the rectified AC voltage increases, once it has reached a non-zero value, thereby providing a current flow through the primary winding and hence through the secondary winding when the switch (111—transistors Q1 & Q2) is switched off. The switch is further arranged to switch off before the rectified AC voltage starts to increase again.

Abstract: A projected on-time (POT) switching regulator is provided. The regulator includes a switching regulator controller and a main switch. The controller includes a feedback comparator and an on-timer. The feedback comparator compares the output voltage to a reference voltage. Whenever the feedback comparator trips, the main switch is turned on, and the on-timer controls the turn-on duration (on-time) of the main switch, where the duration is adjusted by the input and output voltages according to a preset transfer function. The transfer function is applicable to both CCM and DCM operation. However, during CCM mode operation, at least above a minimum on-time, the on-time is adjusted so that the switching frequency of the regulator is approximately constant. The on-timer includes a comparator that compares an adjustable voltage VFQ to a ramp voltage VIFQ generated by providing an adjustable current IFQ to a capacitor CREF.

Abstract: A switching control circuit having a synchronous input for the synchronization of power converters is provided. It includes a synchronous input circuit for receiving a synchronous input signal. An oscillation circuit is connected to the synchronous input circuit for generating an oscillation signal in response to the synchronous input signal. A signal converter is coupled to receive a feedback signal of the power converter for modulating the oscillation signal in response to the feedback signal for achieving power savings. The oscillation signal is connected for enabling the switching signal of the power converter. The switching signal can be synchronized with the synchronous input signal immediately after the synchronous input signal is inputted. Otherwise, the switching signal will be running free.

Abstract: An embodiment of a power-supply controller is operable to couple a first node of a first inductor to first and second reference nodes, the first inductor composing a first phase of a power supply and having a second node coupled to an output node of the power supply. The controller is also operable to couple a first node of a second inductor to third and fourth reference nodes, the second inductor composing a second phase of the power supply and having a second node. Furthermore, the controller is operable to uncouple the second node of the second inductor from the output node of the power supply. For example, where the first and second inductors are magnetically coupled, such a controller allows the power supply to operate as an uncoupled-inductor (UI) power supply in one mode, and as a coupled-inductor (CI) power supply in another mode.

Abstract: Multilevel high power converters, referred to as hexagram converters, which preferably include a combination of six three-phase converter modules, are provided herein. The three-phase converter modules are interconnected and can be configured as any three-phase converter for any given application. One or more inductors can be used in the interconnections between the six modules to suppress potential circulating currents. Numerous applications exist in which the described converters can be implemented.

Abstract: A resonant switching converter comprises a resonant tank having a resonant frequency; a synchronous rectifier coupled to the resonant tank, the synchronous rectifier drawing power from the resonant tank for forming an output voltage; and a controller coupled to the synchronous rectifier for controlling switching of the synchronous rectifier using frequency modulation. The controller operates in a first mode in which the switching of the synchronous rectifier is performed above the resonant frequency of the resonant tank. The first mode employs a duty cycle for the synchronous rectifier. In addition, the controller operates in a second mode in which the switching of the synchronous rectifier is performed below the resonant frequency and the duty cycle of the synchronous rectifier in the second mode is reduced from that of the first mode.

Abstract: An apparatus for synchronous rectifying of a soft switching power converter is provided. An integrated synchronous rectifier includes a power transistor coupled between a transformer and the output of the soft switching power converter, and a controller receiving a pulse signal to switch on/off the power transistor. A switching control circuit generates the pulse signal in response to a current signal, and generates drive signals to switch the transformer in response to a switching signal. An isolation device is coupled to transfer the pulse signal between the switching control circuit and the integrated synchronous rectifier. The switching signal is used for regulating the power converter and the current signal is correlated to the switching current of the transformer.

Abstract: In one embodiment of the present invention, an output control device is disclosed capable of reducing a chip size and realizing a low cost. An output control device includes a switching transistor controlling an output voltage by having an on/off time ratio controlled and a control IC controlling the on/off time ratio of the switching transistor on the basis of the output voltage controlled by the switching transistor. The switching transistor is made of a lateral power MOSFET.

Abstract: In a digital boost or buck-boost converter, a pulse width modulation signal has an on-time and an off-time. A constant off-time period is provided to set the off-time to be constant, and an on-time period to determine the on-time is derived by monitoring the output voltage of the converter. With the constant off-time, the output voltage and the on-time period will have a linear relation, thereby reducing the output ripple when the converter operates with a high duty-ratio.