Anpec Electronics Corporation

Shih-Chung Wei

Ming-Liang Tsai

A power switch circuit of adaptively limiting a current is provided. The power switch circuit includes a current sensing resistor, a power switch, a charge pump and an adaptive current limiting circuit. A first terminal of the current sensing resistor is coupled to an input voltage. A first terminal of the power switch is connected to a second terminal of the current sensing resistor. A second terminal of the power switch is connected to a first terminal of a capacitor. A second terminal of the capacitor is grounded. An output terminal of the charge pump is connected to a control terminal of the power switch. According to the input voltage, a voltage of the current sensing resistor and a voltage of the capacitor, the adaptive current limiting circuit determines whether to control an operation of the power switch for limiting the current flowing through the power switch.

Power switch circuit

A power converter having a mechanism of dynamically controlling a minimum off time is provided. A high-side overcurrent protecting circuit determines whether or not a current flows from a high-side switch through a node between a second terminal of the high-side switch and a first terminal of a low-side switch toward an inductor, and determines whether or not the current is larger than a threshold to output a high-side overcurrent detected signal and a high-side overcurrent protecting signal. An off time adjusting circuit outputs a minimum off time signal to a driver circuit according to the high-side overcurrent protecting signal. The driver circuit determines that an overcurrent event occurs when the high-side switch is turned on according to the high-side overcurrent detected signal, and accordingly the driver circuit at least continually turns on the low-side switch during a longer minimum off time of the minimum off time signal.

Power converter having mechanism of dynamically controlling minimum off time

A current detecting circuit of a constant on-time power converter and a method thereof are provided. The current detecting circuit includes a time detecting circuit and a sample and hold circuit. A control circuit of the constant on-time power converter outputs a lower bridge conduction signal to turn on a lower bridge switch during an on-time of each cycle of the lower bridge conduction signal. The time detecting circuit detects the on-time of a cycle of the lower bridge conduction signal. The sample and hold circuit samples and holds a current of an inductor at a detection time point of a next cycle of the lower bridge conduction signal. A time between a rising edge of a waveform of the next cycle of the lower bridge conduction signal and the detection time point is equal to half the on-time.

Growing community of inventors

Hsinchu, Taiwan

Shih-Chung Wei