Niko Semiconductor Co., Ltd.

Ta-Ching Hsu

Chung-Ming Leng

Chun-Ming Lin

Yun-Kang Chu

A power conversion apparatus is provided. The power conversion apparatus receives an AC input power by an input side and includes a capacitor, an AC-to-DC conversion unit and a discharge unit. The capacitor is connected with the input side. The AC-to-DC conversion unit is coupled to the input side, and configured to convert the AC input power after receiving the AC input power to generate a DC output power. The discharge unit is coupled to the capacitor and has at least two switch elements. The discharge unit enables the at least two switch elements when supply of the AC input power is interrupted, such that one of a first discharge path and a second discharge path formed by the at least two switch elements is taken to discharge or drain the energy stored in the capacitor.

Power conversion apparatus and control chip thereof

A low power consumption bleeder circuit is disclosed, and it is coupled to an alternating-current (AC) power source, an input filtering capacitor, and a rectifying filter. The low power consumption bleeder circuit includes a first switch component, a second switch component, and a controller. The first switch component is coupled to a first input terminal of the AC power source and a first connection terminal of the rectifying filter. The second switch component is coupled to a second input terminal of the AC power source and the first connection terminal of the rectifying filter. When the AC power source is detected to be removed, the controller controls at least one of the first switch component and the second switch component to be conductive.

Alternating-current conversion system having low power consumption bleeder circuit

A conversion control circuit for controlling the operation of a power transistor is disclosed. The conversion control circuit includes a voltage-regulating switch and a control unit. One end of the voltage-regulating switch connects to an external voltage input terminal while another end connects to a voltage-regulating capacitor. The conversion control circuit converts an input voltage inputted from the external voltage input terminal into a power voltage. The power voltage is for supplying operating power to the conversion control circuit. The control unit receives a feedback voltage signal to generate a voltage-regulating pulse signal and a turn-on pulse signal, which are used for controlling the operations of the voltage-regulating switch and the power transistor, respectively and for defining a charging period for charging the voltage-regulating capacitor. A converter including the described conversion control circuit is also disclosed.

Conversion control circuit and converter thereof

A multiphase DC-to-DC converter is disclosed herein, which includes at least one DC-to-DC converting module. Each DC-to-DC converting module at least includes a first output inductor, a second output inductor and a current detector. The current detector is configured for detecting currents pass through the first output inductor and second output inductor. The current detector includes a first resistance, a second resistance, a first capacitor, a second capacitor, and a third resistance. The third resistance is directly or indirectly coupled between the first capacitor and a load circuit, and directly or indirectly coupled between the second capacitor and the load circuit, such that when the first capacitor is charged, a portion of the current charging the first capacitor passes through the second capacitor.

Multiphase DC-to-DC converter

A secondary side synchronous rectification control circuit is disclosed. The control circuit includes an inverted amplifier, a first comparator, and a driving unit. The inverted amplifier has an input end for receiving a drain source voltage signal from a synchronous rectification transistor and outputting an inverted amplification signal. The first comparator receives the inverted amplification signal and a first reference voltage for outputting a first comparison signal. The driving unit receives the first comparison signal and generates a driving signal according to the first comparison signal, for controlling the conduction status of the synchronous rectification transistor. The drain source voltage of the synchronous rectification transistor in the present invention is inverted amplified by an inverted amplifier, and it is connected to a comparator for generating the driving signal. The errors and defects of the turn-off timing of the driving signal may be solved and eliminated.

Secondary side synchronous rectification control circuit and switching converter

A flyback power converter with multiple outputs is disclosed. The flyback power converter has a transformer, a first output circuit, a second output circuit, and a secondary side synchronous rectification controller. The transformer has a primary side winding, a first output winding, and a second output winding. The first output circuit has a first output capacitor for storing electric energy from the first output winding. The second output circuit has a second rectifying switch and a second output capacitor. The second output capacitor is utilized for storing the electric energy from the second output winding. The secondary side synchronous rectification controller controls the conduction time of the second rectifying switch according to a detecting signal of a secondary-side conduction period. The electric energy in the first output capacitor may be transferred to the second output capacitor through the second output winding and the second rectifying switch and vice versa.

Flyback power converter with multiple outputs and a secondary side post regulator thereof

A predictive synchronous rectification controller for controlling at least one synchronous rectification switch is provided. The synchronous rectification controller has a ramp generator, a peak sampling unit, and an output control unit. The ramp generator receives a synchronous signal and generates a ramp signal accordingly. The peak sampling unit generates a predicted reference voltage signal by retrieving a peak voltage of the ramp signal. The output control unit compares the ramp signal with the predicted reference voltage signal to generate a synchronous rectification control signal to control a conducting state of the switch.

Predictive synchronous rectification controller, switching power converter with predictive synchronous rectification controller and controlling method thereof

A flyback power converter with multiple outputs has a transformer, a low-voltage output circuit, a high-voltage output circuit, and a secondary side post regulator circuit is provided. The transformer has a first secondary winding and a second secondary winding. The low-voltage output circuit has a low-voltage output capacitor and a rectifier unit, and is coupled to the first secondary winding to generate a low voltage output. The high-voltage output circuit has a high-voltage output switch and a high-voltage output capacitor, and is coupled to the second secondary winding to generate a high voltage output. The secondary side post regulator circuit adjusts on-time of the high-voltage output switch according to a feedback signal to have the energy stored in the high-voltage capacitor transmitted to the low-voltage capacitor to lower down the voltage level of the high output voltage.

Secondary side post regulator of flyback power converter with multiple outputs

The present invention discloses a primary-side driving backlight circuit for LCD panel. The primary-side driving backlight circuit employs a single isolation device to achieve isolation request for safety for the secondary side. The PWM controller on the secondary-side of a transformer generates a control signal according to a feedback signal. The control signal is transmitted by the isolation device to a High/Low side driver. The High/Low side driver has a High Output and a Low Output, which drives power switches at high side and low side respectively, in order to control the power of an input source transmitting into the transformer and further control the voltage and current of cold cathode lamp(s) of a backlight circuit.

Primary-side driving control circuit for backlight of LCD panel

A synchronous rectifier control device comprises a status detecting unit, an analog circuit, a first counter, a second counter and a signal process unit. The status detecting unit receives at least one reference signal and a detecting signal to generate a first synchronous control signal. The analog circuit generates a delay signal in accordance with the first synchronous control signal. The first counter receives a clock signal and generates a first counter signal in accordance with the first synchronous control signal, the clock signal, and the delay signal. The second counter receives the clock signal and generates a second counter signal in accordance with the first synchronous control signal, the clock signal, and the first counter signal. The signal process unit generates a second synchronous control signal in accordance with the first synchronous control signal and the second signal.

Synchronous rectifier control device and a forward synchronous rectifier circuit

A high voltage start-up circuit with constant current control applied to a switching mode power converter is provided. The high voltage start-up circuit includes a high voltage junction transistor, a control transistor, a current detecting resistor and a bias resistor. The drain of the junction transistor is connected to a high power supply, the gate of the junction transistor is connected to the drain of the control transistor, and the source of the junction transistor is connected to the current detecting resistor. The voltage drop crossing the current detecting resistor is kept constant to have the junction transistor output a constant current. The bias resistor which is connected between the gate of the junction transistor and the output end of the high voltage start-up circuit has the gate to source bias voltage of the junction transistor kept constant to output constant current.

High voltage start-up circuit with constant current control

A three-pin integrated synchronous rectifier is the synchronous rectifier chip where the quantity of connection pins is the smallest possible quantity. The three-pin integrated synchronous rectifier uses a control pin to receive a control signal used as a power bias voltage and a synchronous pulse to make the synchronous rectifier chip operate normally. The control signal is obtained from the output pin of an auxiliary winding via a diode. The other pins are respectively the drain pin and the source pin of an internal power transistor and are connected with the output winding and the voltage output terminal for transmitting the power of the transformer to supply current for the loading.

Three-pin integrated synchronous rectifier and a flyback synchronous rectifying circuit

A PWM controller with output current limitation makes the over-current limitations almost the same even though the input voltages are different. The designer does not need to use high specification components or add an output current limiting circuit against the over-current condition. Costs are reduced and the layout is simplified. The switch power supply includes a transformer, a power switch, a first detecting circuit for generating a first detecting signal, a second detecting circuit for generating a second detecting signal, and a controller. The transformer converts the power and outputs the power to the secondary side. The power switch has a first terminal, a second terminal, and a controlled terminal. The controller has a control terminal, a first detecting terminal for receiving the first detecting signal, and a second detecting terminal for receiving the second detecting signal. The controller performs a protecting operation according to the received signals.

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Taipei, Taiwan

Ta-Ching Hsu