Abstract: A secondary circuit of a flyback power converter has a resistor network to monitor the output current of the flyback power converter, so as to generate a voltage to apply to a base of a bipolar junction transistor to thereby provide a collector signal for output feedback. The resistor network has a temperature-dependent resistance to compensate the temperature dependence of the base-emitter voltage imparted to the output current and thereby stable the output current.

Abstract: The present invention discloses a switching regulator control circuit which distinguishes the output short-circuit condition, which imposes immediate danger, from other mild over current conditions. The switching regulator control circuit includes: an over current judgment circuit comparing a current sense signal with a current limit to generate an over current indication signal; a time comparison circuit comparing the over current indication signal with a clock signal to generate an output short-circuit indication signal; and a timer receiving the over current indication signal and the output short-circuit indication signal, wherein when the output short-circuit indication signal does not indicate output short-circuit, the timer counts a first time period, and when the output short-circuit indication signal indicates output short-circuit, the timer counts a second time period shorter than the first time period, for better safety protection.

Abstract: The present invention discloses an integrated PMOS transistor and Schottky diode, comprising a PMOS transistor which includes a gate, a source, a drain and a channel region between the source and drain, wherein the source, drain and channel region are formed in a substrate, and a parasitic diode is formed between the drain and the channel region; and a Schottky diode formed in the substrate and connected in reverse series with the parasitic diode, the Schottky diode having one end connected with the parasitic diode and the other end connected with the source.

Abstract: A pulse width modulation controller and method for output ripple reduction of a jittering frequency switching power supply detect the current of a power switch of the switching power supply to generate a current sense signal, and adjust the gain or the level of the current sense signal according to the switching frequency of the power switch to adjust the on time of the power switch, to reduce the output ripple of the switching power supply caused by the jittering frequency of the switching power supply.

Abstract: A jittering frequency control circuit and method for a switching mode power supply enlarge the uttering frequency range of the switching frequency of the switching mode power supply when the switching mode power supplier enters a frequency reduction mode, to improve the electro-magnetic interference of the switching mode power supply operating with the frequency reduction mode.

Abstract: A method for generating a current limit signal for a power converter without sensing an input voltage of the power converter detects a current of a power switch of the power converter to obtain a current sense signal, counts a time for the current sense signal to increase from a first level to a second level, and according to the time, determines a current limit signal for limiting a maximum value of the current of the power switch for the power converter to have a constant maximum output power.

Abstract: A circuit and method are provided for a power converter to select one from a plurality of current limit signals as a final current limit signal according to the present duty ratio of a power switch for the pulse width modulation of the next cycle, so that the duty ratio of the power switch in the next cycle is prevented from acute variation to eliminate sub-harmonic which otherwise may happen.

Abstract: A circuit and method are disclosed for providing smart protection to a battery pack against abnormal operation with an electrical switch. The battery cell of the battery pack is monitored to control the electrical switch. If abnormal operation occurs, the electrical switch will turn off to disconnect the battery cell. Once the abnormal condition disappears, the electrical switch will turn on and the battery cell will return to normal state.

Abstract: A voltage detector includes a zener diode having a cathode connected to a detect terminal of the voltage detector, a junction field effect transistor having an input terminal connected to an anode of the zener diode, and a resistor connected between an output terminal and a control terminal of the junction field effect transistor. When the voltage on the detect terminal is higher than the breakdown voltage of the zener diode, the junction field effect transistor produces a current flowing through the resistor, and thereby a detection signal can be obtained from the voltage across the resistor.

Abstract: A switch embedded integrated circuit for battery protection includes a MOSFET having a body diode, and a control logic circuit for switching the MOSFET and the direction of the body diode to control the charge current to and the discharge current from a battery. The control logic circuit turns off the MOSFET once any abnormal operation such as over-voltage and under-voltage happens, and turns on the MOSFET according to an OVPR threshold, an OVPR delay time, an UVPR threshold and an UVPR delay time. The OVPR threshold and the OVPR delay time are determined depending on the battery being coupled to a load or a charger, or floating.

Abstract: A controller chip provides protection to a power converter by using a high-voltage start-up device in the controller chip, without additional pins or external elements of the controller chip. A JFET is used as the high-voltage start-up device connected between a high-voltage pin and a power input pin of the controller chip, to charge a power capacitor connected to the power input pin at power on. The controller chip monitors the voltage at the power input pin and turns off the JFET once the voltage at the power input pin increases to reach a threshold. Thereafter, the source voltage of the JFET will reflect the voltage at the high-voltage pin, and a protection circuit monitors the source voltage of the JFET to trigger a protection signal.

Abstract: An apparatus and method for a flyback power converter reduce the standby output voltage of the flyback power converter by switching the reference voltage provided by a shunt regulator of the flyback power converter or the ratio of voltage divider resistors of the shunt regulator, to reduce the standby power consumption by an output feedback circuit of the flyback power converter, the shunt regulator, and the voltage divider resistors, and thereby the power loss of the flyback power converter in standby mode.

Abstract: A display includes a power supply system using a power controller to switch a power switch to control power delivery, and an image scalar receiving a supply voltage and a supply current from the power supply system. An apparatus and method are proposed to determine a control signal in a standby mode by monitoring the supply voltage or the supply current, to wake up or turn off the power controller to reduce the switching times of the power switch in the standby mode, thereby reducing the switching loss of the power switch and the standby power consumption of the display.

Abstract: A secondary circuit of a flyback power converter has a resistor network to monitor the output current of the flyback power converter, so as to generate a voltage to apply to a base of a bipolar junction transistor to thereby provide a collector signal for output feedback. The resistor network has a temperature-dependent resistance to compensate the temperature dependence of the base-emitter voltage imparted to the output current and thereby stable the output current.

Abstract: A charger has two pins for connecting with a battery therebetween, and an apparatus and method are proposed to determine to wake up or turn off the charger according to a voltage or a current detected from the two pins, to reduce the standby power consumption of the charger.

Abstract: An isolated type power supply includes a transformer, and a power switch and a current sense resistor serially connected to a primary coil of the transformer, and a protection apparatus and method monitor a control signal which is used to switch the power switch in normal operation, and trigger a signal to stop the power from switching when the control signal becomes greater than a threshold. This protection apparatus and method can more quickly detect short circuit of the current sense resistor, and prevent the isolated type power supply from overcurrent impact.

Abstract: Disclosed are methods of detection for output short circuit of a flyback power supply, which detect the current sense signal provided by a current sense resistor serially connected to a power switch of the flyback power supply, and thus quickly identify whether or not the flyback power supply suffers output short circuit.

Abstract: A state cycling apparatus uses a capacitor instead of complicated and expensive microcontroller to fulfill a state cycling function of a system. The state cycling apparatus includes an internal circuit in the system connected to the capacitor. In a first embodiment, the internal circuit reads the voltage level on the capacitor at power on to determine a current state for the system, and writes the voltage level corresponding to a next state of the system to the capacitor. In a second embodiment, the system reads the state data stored in the internal circuit to determine a current state for the system at power on, the capacitor is charged during the system is under power on, and the capacitor provides power for the internal circuit to store a state data after the system is powered off.

Abstract: A switch embedded integrated circuit for battery protection includes a first pin to be connected with one terminal of a battery, a second pin to be connected with a load or charger, a third pin to be connected with another terminal of the battery, a MOSFET having a body diode thereof and connected between the first and second pins, a control logic circuit and a detection circuit. The detection circuit monitors the voltage between the first pin and the third pin to determine a detection signal for the control logic circuit to turn on or off the MOSFET and switch the direction of the body diode, thereby providing an over charging and an over discharging protection functions.