Abstract: A switching power supply includes a switching unit, a driving signal generator, and a control circuit. The driving signal generator is configured for providing a driving signal including a plurality of acting voltage parts. The plurality of acting voltage parts is used to turn on the switching unit. Each of the acting voltage parts may be one of a high level voltage and a low level voltage. The control circuit is connected between the driving signal generator and the switching unit. The control circuit turns off the switching unit when a duration of one of the plurality of acting voltage parts is longer than a preset time period.

Abstract: A power supply module includes a rectifying and filtering unit, a pulse width modulation (PWM) unit, a voltage transforming unit, a sampling and comparing unit, and an overvoltage protection unit. The rectifying and filtering unit receives an alternating current (AC) voltage, and generates a filtered primary DC voltage. The PWM unit is configured for generating pulses. The voltage transforming unit transforms the filtered primary DC voltage into the DC voltage according to the pulses. The sampling and comparing unit samples the DC voltage, and generates an overvoltage signal when the sampled DC voltage exceeds a predetermined DC voltage. The overvoltage protection unit is coupled between the sampling and comparing unit and the PWM unit. According to the overvoltage signal, the overvoltage protection unit generates a first control signal to disable the PWM unit, and the overvoltage protection unit is self-locked.

Abstract: A power supply module includes an AC/DC converter, a voltage transforming circuit, a feedback circuit, and a filtering circuit. The AC/DC converter is used for converting the AC voltage to a primary DC voltage. The voltage transforming circuit is configured for transforming the primary DC voltage to the first DC voltage. The voltage transforming circuit includes a transformer, the transformer includes a primary winding. The feedback circuit is coupled to the primary winding of the transformer and is configured for sampling a current flowing through the primary winding to generate a feedback signal; and the filtering circuit is structured and arranged for filtering any surge voltage transmitted from the feedback circuit to the voltage transforming circuit. Wherein the voltage transforming circuit maintains the first DC voltage at a predetermined value according to the feedback signal. A related power supply module assembly is also provided.

Abstract: A power supply includes an adapter and a delay module. The adapter is operable to receive an input voltage and convert the input voltage into a first operation voltage to power a load controlled by a control unit. The adapter includes a filter capacitor configured to smooth the first operation voltage. The delay module detects the input voltage, and supplies a second operation voltage to the control unit when receiving the input voltage. The delay module continues supplying the second operation voltage to the control unit for a predetermined time period after the input voltage is no longer supplied to the adapter. As a result, the load operates for at most the predetermined time period and the filter capacitor discharges via the load after the input voltage is removed.

Abstract: A power supply module includes an AC/DC converter, a voltage transforming circuit, a feedback circuit, and a detecting circuit. The AC/DC converter is used for converting the input AC voltage to a primary DC voltage. The voltage transforming circuit is used for transforming the primary DC voltage to the first DC voltage. The feedback circuit is used for sampling the first DC voltage to generate a feedback signal. The detecting circuit is used for detecting if the power supply module is powered on, and generating a first voltage when detecting that the power supply module is powered on. Wherein the voltage transforming circuit maintains the first DC voltage at a first predetermined value according to the feedback signal, the feedback circuit increases a magnitude of the feedback signal according to the first voltage.

Abstract: A power supply module is configured for converting an AC voltage to a first DC voltage and applying the first DC voltage to a load. The power supply module includes a rectifying and filtering unit, a PFC unit, a voltage transforming unit, an input port, and a switch unit. The rectifying and filtering unit rectifies the AC voltage into a primary DC voltage and filters the primary DC voltage. The PFC unit corrects a power factor of the filtered primary DC voltage. The voltage transforming unit converts the corrected primary DC voltage and generates the first DC voltage for applying the load. The input port receives a first instruction or a second instruction and generates a first signal or a second signal, respectively. The switch unit establishes or disconnects an electrical connection between the voltage transforming unit and the load according to the first signal or the second signal.

Abstract: An exemplary backlight control circuit (200) includes a DC power supply (VDD), a load circuit (210), an input circuit (230), and a PWM IC (250). The load circuit includes two light sources (2113, 2114) and a rectifier and filter circuit (213). The input circuit includes a diode (231) and a capacitor (237). The PWM IC includes a current sampling pin (251) and an overvoltage protection pin (253). A low voltage terminal of a first one of the two light sources is connected to the current sampling pin via the rectifier and filter circuit, and a low voltage terminal of a second one of the two light sources is connected to a cathode of the diode. An anode of the diode is connected to the DC power supply and grounded via the capacitor. The overvoltage protection pin is connected to the DC power supply.

Abstract: An exemplary backlight driving circuit (20) a first power supply (260); a second power supply (270); a signal output terminal (280); an AND gate (210); a follower (220); a capacitor (290); a reverser (230); a first transistor (240), which is a N-Channel mode metal-oxide-semiconductor field-effect transistor (N-MOSFET), having a gate electrode connected to an output end of the AND gate through the follower, a source electrode connected to the signal output terminal, a drain electrode connected to the first power supply; and a second transistor (250), which is a N-Channel mode metal-oxide-semiconductor field-effect transistor (N-MOSFET), having a gate electrode connected to the output end of the AND gate through the reverser, a source electrode connected to the ground, a drain electrode connected to the signal output terminal.

Abstract: A square wave generator includes a sawtooth wave generator for generating a sawtooth wave, and a convertor for generating a square wave based on the sawtooth wave. The sawtooth wave generator includes a capacitor and a switching unit connected parallel to each other. A first terminal of the capacitor is electrically coupled to a power source and the convertor, and a second terminal of the capacitor is grounded. The switching unit includes a trigger and a field-effect transistor. When a voltage of the first terminal of the capacitor is not less than a first threshold voltage of the trigger, the trigger is turned on to activate the field-effect transistor, the field-effect transistor is turned on to ground the first terminal of the capacitor, so that the capacitor discharges rapidly.

Abstract: An exemplary direct current to alternating current converter includes a pulse width modulator having a plurality of pulse signal outputs that can provide a plurality of pulse signals, a driving circuit having a plurality of switching units, and a transformation circuit having a plurality of transformers. Each of the switching units includes a P-type transistor and an N-type transistor. Each pulse signal output is electrically connected to the P-type and N-type transistors of one of the switching units. Each of the transformers is connected to two of the switching units, and the P-type transistors and the N-type transistors of the two switching units are not switched on simultaneously.

Abstract: An exemplary DC to DC converter (2) includes a transistor (29), a first rectifying and filtering circuit (21), a pulse generating circuit (27) and a transformer (25). The first rectifying and filtering circuit transforms an external AC voltage to a first DC voltage. The transformer includes a primary winding (251), an assistant winding (252) connected with the primary winding in a flyback mode, and a secondary winding (253). The first DC voltage is connected to ground via the primary winding, the transistor in series. The pulse generating circuit includes a controlling terminal, a diode, a resistor, and a capacitor. One terminal of the assistant winding is connected to ground, and the other terminal of the assistant winding is connected to an anode of the diode. A cathode of the diode is connected to ground via the resistor and the capacitor in series. The controlling terminal is connected to gate electrode of the transistor.

Abstract: An exemplary power supply control circuit (200) includes a first port (201), a second port (202), a third port (203), a controllable switch (280), and a control circuit (270). The first and second ports are configured to receive a power supply voltage signal. The second and third ports are configured to output the power supply voltage signal to a load circuit. The controllable switch includes a control member (281) and a switch member (282). The control circuit is configured to control a working state of the control member. When the load circuit stops working, the control circuit controls the control member to control the switch member to be disconnected, so as to cut off the power supply voltage signal from outputting to the load circuit. A liquid crystal display (400) using the power supply control circuit is also provided.

Abstract: A switching power supply includes a switching unit, a driving signal generator, and a control circuit. The driving signal generator is configured for providing a driving signal including a plurality of acting voltage parts. The plurality of acting voltage parts is used to turn on the switching unit. Each of the acting voltage parts may be one of a high level voltage and a low level voltage. The control circuit is connected between the driving signal generator and the switching unit. The control circuit turns off the switching unit when a duration of one of the plurality of acting voltage parts is longer than a preset time period.

Abstract: A power supply module includes a rectifying and filtering unit, a pulse width modulation (PWM) unit, a voltage transforming unit, a sampling and comparing unit, and an overvoltage protection unit. The rectifying and filtering unit receives an alternating current (AC) voltage, and generates a filtered primary DC voltage. The PWM unit is configured for generating pulses. The voltage transforming unit transforms the filtered primary DC voltage into the DC voltage according to the pulses. The sampling and comparing unit samples the DC voltage, and generates an overvoltage signal when the sampled DC voltage exceeds a predetermined DC voltage. The overvoltage protection unit is coupled between the sampling and comparing unit and the PWM unit. According to the overvoltage signal, the overvoltage protection unit generates a first control signal to disable the PWM unit, and the overvoltage protection unit is self-locked.

Abstract: A power supply module includes an AC/DC converter, a voltage transforming circuit, a feedback circuit, and a filtering circuit. The AC/DC converter is used for converting the AC voltage to a primary DC voltage. The voltage transforming circuit is configured for transforming the primary DC voltage to the first DC voltage. The voltage transforming circuit includes a transformer, the transformer includes a primary winding. The feedback circuit is coupled to the primary winding of the transformer and is configured for sampling a current flowing through the primary winding to generate a feedback signal; and the filtering circuit is structured and arranged for filtering any surge voltage transmitted from the feedback circuit to the voltage transforming circuit. Wherein the voltage transforming circuit maintains the first DC voltage at a predetermined value according to the feedback signal. A related power supply module assembly is also provided.

Abstract: An exemplary inverter circuit (200) includes a direct current (DC) input terminal (210); a transformer (230) including a first primary winding (231) and a second primary winding (232); a first switch transistor (240); a second switch transistor (250); a pulse generator (260) providing pulse driving signals to the first switch transistor and the second transistor respectively; and a resistor (29). The first primary winding and the second primary winding share a tap (235), the tap is connected to the DC input terminal via the resistor. A drain electrode of the first switch transistor is connected to the tap via the first primary winding, and a drain electrode of the second switch transistor is connected to the tap via the second primary winding.

Abstract: A power supply module is configured for converting an AC voltage to a first DC voltage and applying the first DC voltage to a load. The power supply module includes a rectifying and filtering unit, a PFC unit, a voltage transforming unit, an input port, and a switch unit. The rectifying and filtering unit rectifies the AC voltage into a primary DC voltage and filters the primary DC voltage. The PFC unit corrects a power factor of the filtered primary DC voltage. The voltage transforming unit converts the corrected primary DC voltage and generates the first DC voltage for applying the load. The input port receives a first instruction or a second instruction and generates a first signal or a second signal, respectively. The switch unit establishes or disconnects an electrical connection between the voltage transforming unit and the load according to the first signal or the second signal.

Abstract: A power supply module includes an AC/DC converter, a voltage transforming circuit, a feedback circuit, and a detecting circuit. The AC/DC converter is used for converting the input AC voltage to a primary DC voltage. The voltage transforming circuit is used for transforming the primary DC voltage to the first DC voltage. The feedback circuit is used for sampling the first DC voltage to generate a feedback signal. The detecting circuit is used for detecting if the power supply module is powered on, and generating a first voltage when detecting that the power supply module is powered on. Wherein the voltage transforming circuit maintains the first DC voltage at a first predetermined value according to the feedback signal, the feedback circuit increases a magnitude of the feedback signal according to the first voltage.

Abstract: A transformation circuit includes a bidirectional switch, a capacitor, and a triac. A first electrode of the triac is for receiving an input alternating current (AC) voltage. A second electrode of the triac is for outputting a transformed AC voltage. A control electrode of the triac is electrically connected to one terminal of the bidirectional switch, and the other terminal of the bidirectional switch is electrically connected to one terminal of the capacitor, and the other terminal of the capacitor is electrically connected to the first electrode of the triac. When the capacitor is charged or discharged, the bidirectional switch is switched on or off, and the triac is triggered on or off accordingly, such that a duty cycle of the input AC voltage is changed to form the transformed AC voltage.

Abstract: An exemplary inverter circuit (2) includes a first switch circuit (22) including a first transistor (221) and a second transistor (222); a second switch circuit (23) including a third transistor (231) and a fourth transistor (232); and a pulse width modulation circuit (21) including a first output terminal (211) and a second output terminal (212). A gate electrode of the first transistor is connected to the first output port. A gate electrode of the second transistor is connected to the second output port. A gate electrode of the third transistor is connected to the first output port. A gate electrode of the fourth transistor is connected to the second output port. A drain electrode of the third transistor is connected to a drain electrode of the first transistor, and a drain electrode of the fourth transistor is connected to a drain electrode of the second transistor.