Abstract: According to one aspect of the invention, a DC-DC converter including a soft-start function of a soft start in response to a soft-start signal, comprises: a detection circuit that detects whether the soft-start signal is active at an end of a soft-start operation; and an output voltage control circuit that controls an output voltage based on detection result of the detection circuit.

Abstract: A step-up DC-DC converter is disclosed that is capable of high efficiency power conversion under both a heavy load condition and a light load condition. The step-up DC-DC converter includes a direct current power source, an inductor, a first switching element, a second switching element, a smoothing capacitor, a driver controller for controlling switching ON or switching OFF the first switching element and the second switching element, and a control changing unit for changing a control operation of the driver controller according to a load current. According to an output from the control changing unit, the driver controller performs one of an operation of switching OFF the second switching element and an operation of switching ON or switching OFF the second switching element.

Abstract: A method and apparatus for converting a DC voltage to a lower DC voltage, provides for conducting current from an input terminal, through an inductor to charge a capacitor connected to the inductor at an output terminal and to provide a varying range of load current from the output terminal, alternately switching the input terminal between a supply voltage and a ground potential to produce a desired voltage at the output terminal that is lower than the supply voltage, while providing the varying range of load current, and disconnecting the input terminal from both the supply voltage and the ground potential to reduce an increase in voltage at the output terminal caused by a substantial reduction in the load current, while current through the inductor adjusts in response to the reduced load current.

Abstract: A synchronous rectifying circuit of a resonant switching power converter is provided to improve the efficiency. The synchronous rectifying circuit includes a power transistor and a diode connected to a transformer and an output ground of the power converter for rectifying. A sense transistor is coupled to the power transistor for generating a mirror current correlated to a current of the power transistor. A controller generates a driving signal to control the power transistor in response to a switching-current signal. A current-sense device is coupled to the sense transistor for generating the switching-current signal in response to the mirror current. The controller enables the driving signal to turn on the power transistor once the diode is forwardly biased. The controller generates a reset signal to disable the driving signal and turn off the power transistor once the switching-current signal is lower than a threshold.

Abstract: Disclosed is a current mode switched power supply. The current mode switched power supply includes a switching element and a power stage coupled to the switching element and configured to provide, in response to the switching of the switching element, an output voltage and a feedback voltage related to the output voltage. The current mode switched power supply also includes a digital control circuit connected to the switching element to digitally control the switching of the switching element.

Abstract: An integrated circuit die includes a microprocessor and a control circuit to control elements of a voltage regulator to supply power to the microprocessor.

Abstract: A power modulator comprises a plurality of switched pulse generator sections (22), a power supply arrangement (10), and a transformer arrangement (30). A switch control (24) is connected to said plurality of switched pulse generator sections (22) for providing control signals for turning on and/or turning off them. The switch control (24) is arranged to provide control signals for turning on and/or turning off switched pulse generator sections of a first subset at a first time instant and to provide control signals for turning on and/or turning off switched pulse generator sections of a second subset at a second time instant, different from the first time instant: The second subset is different from the first subset.

Abstract: An exemplary power supply circuit (200) includes a pulse width modulation circuit (220) providing a pulse signal, a voltage conversion circuit (210) converting a primary voltage to an output voltage according to the pulse signal, a feedback circuit (260), and a control circuit (290). The feedback circuit includes a sampling branch (261) detecting a current of the voltage conversion circuit and accordingly providing a feedback signal, and a voltage division branch (262) electrically coupled to the sampling branch. The control circuit is electrically coupled to the voltage division branch, and is configured for disabling the voltage division branch after a predetermined period of time when the output voltage is within a predetermined range.

Abstract: A detection circuit for generating a control signal for controlling output voltage of an AC adapter. The detection circuit for an electronic device receives power information from an external power supply via a cable to generate the control signal that controls DC input voltage output from the external power supply. In the detection circuit, a correction voltage generation circuit generates a correction voltage in correspondence with the parasitic resistance of the cable. A power information correction circuit corrects the power information provided from the external power supply via the cable with the correction voltage to generate corrected power information. A detection signal generation circuit calculates the total power amount of the electronic device and generates a power detection signal corresponding to the total power amount. The control signal generation circuit generates the control signal based on the corrected power information and the power detection signal.

Abstract: A switch-mode synchronous boost voltage regulator is disclosed that includes a boost voltage regulator and an active current modulator. The active current modulator detects a negative current flowing through the high-side switch during a light load condition. When the negative current is detected, the active current modulator is operable to maintain the high-side switch “on” in a linear mode and to limit the negative current to a predetermined current level.

Abstract: A power control system includes a switching power converter and a controller, and the controller responds to a time-varying voltage source signal by generating a switch control signal having a period that varies in accordance with at least one of the following: (i) the period of the switch control signal trends inversely to estimated power delivered to a load coupled to the switching power converter, (ii) the period of the switch control signal trends inversely to instantaneous voltage levels of the voltage source signal, and (iii) the period of the switch control signal trends directly with a line voltage level of the time-varying voltage source signal. In at least one embodiment, the controller achieves an efficient correlation between the switching period with associated switching losses and the instantaneous power transferred to the switching power converter while providing power factor correction (PFC).

Abstract: A power conversion system comprises: a source of multiphase high frequency alternating current (AC) electrical input power; a high frequency controlled magnetics transformer for each phase of the multiphase high frequency AC input power, with each transformer having a primary winding coupled to its respective phase of the multiphase high frequency AC input power, at least one secondary winding that produces high frequency AC output power and at least one control winding responsive to a direct current (DC) control signal that changes the high frequency output power in proportion to the amplitude of the DC control signal; a power converter that receives the multiphase high frequency AC output power from each high frequency transformer secondary and converts it to system output power without the high frequency AC content; and a system controller responsive to the system output power that produces a DC control signal for each control winding that changes in amplitude in response to changes in a measured parameter

Abstract: A DC/AC cold cathode fluorescent lamp (CCFL) inverter circuit includes a transformer with a primary winding and a secondary winding for providing increased voltage to a CCFL, a first and second MOSFET switches for selectively allowing direct current of a first polarity and a second polarity to flow through the transformer respectively. The primary and secondary windings of the transformer are electrically coupled to ground. A capacitor divider is electrically coupled to the CCFL for providing a first voltage signal representing a voltage across the CCFL. A first feedback signal line receives the first voltage signal. A timer circuit is coupled to the first feedback signal line for providing a time-out sequence of a predetermined duration when the first voltage signal exceeds a predetermined threshold. A protection circuit shuts down the first switch and the second switch when the first voltage signal exceeds the predetermined threshold after the predetermined duration.

Abstract: A switch-mode DC/DC converter and a linear low drop out (LDO) DC/DC regulator are connected in parallel to drive a single load. Both regulators share a common voltage reference, feedback network, input supply and output such that the regulated voltage is identical during each mode of operation. During heavy loads the switch-mode regulator is in operation and the linear regulator is disabled for the highest efficiency possible. Conversely at light loads the linear regulator is in operation with the switch-mode regulator disabled, also maximizing the efficiency. Each regulator senses load current to automatically transition between the appropriate voltage regulators at fixed load current levels. The presented invention also includes a make before break transition scheme of the voltage regulators to minimize the voltage transients.

Abstract: A switch control device, a switch control method, and a converter using the same are disclosed. The converter includes: a switch; an energy transfer element that converts input energy into output energy according to a switching operation of the switch; and a switch control device that generates a first signal, which is maintained at a first level during a first interval starting from a first time at which the switch is turned on by using a feedback signal corresponding to the output energy and is then gradually lowered from the first level to the feedback signal during a second interval, and controls the switching operation of the switch by using a second signal corresponding to a current flowing at the switch and the first signal. A malfunction due to an LEC can be effectively prevented, and the converter and the converter controller can be implemented to be compact and low-priced.

Abstract: A method for controlling a power supply is disclosed. An example method includes deactivating the power supply in response to a first current through a first terminal of a power supply controller falling below a first threshold value. The power supply is activated in response to the first current through the first terminal rising above a second threshold value. Deactivating the power comprises causing a power switch coupled to a primary winding of the power supply not to receive a switching waveform for more than one cycle until the power supply is activated.

Abstract: A switch controller compensates the total on-time delay of the switch in a switching power converter. The intended on-time of the switching transistor for the present switching cycle is reduced by the time difference between the actual on-time and the intended on-time of the switching transistor in the previous switching cycle in the switching power converter. The total delay of the switch in the switching power converter, including propagation delay, switch turn-on delay, and switch turn-off delay, can be compensated in real time, cycle by cycle.

Abstract: TRIAC or SCR based dimmer circuits with temperature compensation features to enable them to also function properly with outdoor line or low voltage AC light fixtures. The TRIAC's or the SCR's operate as static switches that are ideal for driving directly resistive loads, such as incandescent lamps, in line or low voltage AC dimmer circuits. The performance of this type of a circuit is very temperature dependent but it can be compensated for temperature related changes in the output or load RMS voltage by means of preventing variations in the trigger angle the circuit is running at. Temperature compensation is achieved by means of zener diodes being incorporated in the trigger circuit section of a TRIAC or an SCR based dimmer circuit.

Abstract: A low dropout (LDO) regulator for generating an output voltage on an output from an input voltage of an input source. The LDO regulator including a switch module to generate the output voltage. The switch module including at least two parallel connected switches responsive to corresponding switch control signals to regulate a flow of energy from the input source to the output. Each of the switches having an on-state and an off-state. A digital controller to sense the output voltage and in response to generate the switch control signals such that the output voltage is regulated to a predetermined amplitude.

Abstract: In one embodiment, a power converter system includes a switching circuitry having a plurality of switches operable to be turned on and off to cause current to flow to deliver power to a load. A driver circuitry is responsive to an oscillation signal and generates control signals for turning on and off the switches in the switching circuitry. A free-running oscillator circuitry provides the oscillation signal to the driver circuitry. The free-running oscillator circuitry has an operational amplifier. A frequency of the oscillation signal will be higher if the operational amplifier outputs a first value, and the frequency of the oscillation signal will be lower if the operational amplifier outputs a second value.