Leadtrend Technology Corporation

Da-Chun Wei

Yi-Lun Shen

Yi-Shan Chu

Ju-Lin Chia

Ming-Chang Tsou

Meng-Jen Tsai

Wen-Chung Yeh

Yuan-Wen Chang

Chih-Chi Chang

A control circuit applied to a power converter includes a multi-functional pin, a zero-crossing signal generator, and an over-voltage detector. The multi-functional pin is used for receiving an auxiliary current generated by an auxiliary winding of the power converter, and an input current. The zero-crossing signal generator is used for generating a zero-crossing signal according to the auxiliary current. The over-voltage detector is used for generating an over-voltage signal according to the auxiliary current. The control circuit generates a switch control signal to the power switch according to the zero-crossing signal, or generates an over-voltage protection signal to the power switch according to the over-voltage signal.

Control circuit applied to a power converter and operation method thereof

A compensation circuit has a resistor, a switch and a compensation capacitor. The resistor and the switch are connected in series between a power node and a compensation node. The compensation capacitor is connected to the compensation node, whose voltage is responsive to the output power source. For a predetermined period of time after the voltage falls below a predetermined value, the switch is open and no current flows through the resistor from the power node to the compensation node.

Compensation circuits and control methods of switched mode power supply

An AC/DC power supply with over-voltage protection includes a voltage converting circuit and a digital latch control circuit. The voltage converting circuit has a first-side winding, a second-side winding, and an auxiliary winding for providing a supply voltage according to the AC input voltage. The digital latch control circuit is coupled to the voltage converting circuit and utilized for latching a voltage level of the supply voltage at a first predetermined level according to an over-voltage protection (OVP) trigger signal, where the voltage converting circuit is disabled when the voltage level is latched at the first predetermined level.

Digital latch control circuit for over-voltage protection and power converter using the control circuit

A light emitting device driving circuit, includes: a switch device, a comparator, a driving module, a time counting circuit and a compensation module. The switch device is turned on or off according to a control signal for controlling a driving current flowing through the light emitting device. The comparator generates a comparison result according to a reference voltage and a feedback voltage corresponding to the driving current. The driving module generates the control signal according to the comparison result. The time counting circuit controls the driving module to turn on the switch device after the switch device turns off for a predetermined time. The compensation module detects a turn on time for the switch device and a delay time between the feedback voltage reaching the reference voltage value and the control signal varying correspondingly, and adjusts the reference voltage according to the turn on time and the delay time.

Driving circuit for light emitting device with compensation mechanism and driving method thereof

A pseudo random clock generator includes a clock generator for generating a clock signal. A pseudo random code generator receives the clock signal and thereby generating a pseudo random code. A code limiter enables the value of the pseudo random code being unchanged for at least two periods of the clock signal. A logic gate applies a logic operation to the pseudo random code and the clock signal and thereby outputting a pseudo random clock.

Pseudo random clock generator

Disclosed is a DC to DC converter, which comprises: a transforming circuit, for transforming an input voltage to an output voltage; a comparator, for comparing a reference voltage and a feedback voltage proportional to the output voltage to generate a comparing signal; a control circuit, coupled to the transforming circuit and the comparator, for controlling the transforming circuit according to the comparing signal; and a time-counting device, coupled to the control circuit, for counting the time of a specific voltage level of the comparing signal; wherein the time-counting device informs the control circuit that a load open situation occurs if the specific voltage level of the comparing signal lasts a predetermined time, then the control circuit turns off the transforming circuit.

DC to DC converter with load open detection and related method thereof

A pulse-width-modulation control circuit of a switching-mode power converter with a primary-side feedback control is disclosed. The switching-mode power converter includes a transformer, a power switch, a current sensing resistor and the pulse-width-modulation control circuit. The transformer includes a primary-side winding, a secondary-side winding and an auxiliary winding. The pulse-width-modulation control circuit includes a sample and hold circuit, a transconductor circuit, an error amplifier and a pulse-width-modulation generator.

Switching-mode power converter and pulse-width-modulation control circuit with primary-side feedback control

A dual loop voltage regulation circuit of power supply chip is provided, comprising a capacitor for providing a voltage signal, a comparator for comparing a first reference voltage signal and the voltage signal to output forward or backward trigger signal, a first switch triggered by a forward trigger signal, a second switch triggered by a backward trigger signal, a first operational amplifier generating a first drive signal while the first and second switches are on, a first transistor switch triggered to be on by a first drive signal to provide a current source loop, a third switch triggered by a forward trigger signal, a fourth switch triggered by a backward trigger signal, a second operational amplifier generating a second drive signal while the third and fourth switches are on, and a second transistor switch triggered to be on by a second drive signal to provide a current sink loop.

Dual loop voltage regulation circuit of power supply chip

A protection circuit of the memory module and method thereof are provided. The protection circuit includes: a first voltage comparing unit, which compares a reference voltage signal with a voltage level signal to output a first driving signal; a transistor switch, which is connected among the output terminal of the first voltage comparing unit and the input terminal of the second voltage comparing unit and a power end, wherein the voltage level signal and the threshold voltage signal is compared by the second voltage comparing unit so as to output a second driving signal to a logical algorithm unit, and a logical algorithm is conducted between the second driving signal and system enable signal to output a third driving signal; and a soft start enable unit for receiving the third driving signal so as to enable a soft start process.

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Hsin-Chu, Taiwan

Da-Chun Wei