Realtek Semiconductor Inc.

Li-Cheng Chu

Leaf Chen

Ya-Hsuan Sung

A PWM-based (pulse width modulation-based) overcurrent protection circuit and an operating method for the same are provided. The PWM-based overcurrent protection circuit includes a pulse-width-modulation circuit that is connected to a charge pump and a load detection circuit of a power-switch circuit. The charge pump outputs a voltage to the power-switch circuit according to a clock-voltage signal. The load detection circuit is used to detect an overcurrent flowing through the power-switch circuit according to a load at an output end of the power-switch circuit. Thus, when the load detection circuit detects the overcurrent, the pulse-width-modulation circuit controls a duty-cycle width of the charge pump, so as to suppress the voltage outputted by the charge pump. Therefore, an output voltage from the power-switch circuit can be corrected for preventing or reducing the overcurrent.

Pulse width modulation-based overcurrent protection circuit and operating method for the same

An electronic device having a universal serial bus (USB) power delivery function includes a connector, an electrostatic discharge (ESD) protection circuit, a power reception notification circuit, and a control circuit. The connector is coupled to a USB host. The connector includes a configuration channel (CC) pin. The power reception notification circuit is configured to turn on, in response to an enable signal, a pull-down path of a pull-down circuit of the ESD protection circuit. The configuration channel pin generates a pull-down voltage through the pull-down path of the pull-down circuit when the pull-down path is turned on. The control circuit is configured to send the enable signal to the power reception notification circuit when a trigger signal that meets a power reception condition is detected. The control circuit controls the connector to draw power from the USB host when the pull-down voltage of the connector is greater than a pull-down threshold.

Electronic device having USB power delivery function

The present invention discloses a USB signal output circuit having reverse current prevention mechanism. A switch circuit turns on when a switch control terminal receives a first high level voltage to output a signal from a signal input terminal to a signal output terminal. A first voltage pull-low circuit includes a passive-component high-pass filter circuit and a discharging circuit. The passive-component high-pass filter circuit couples an output terminal voltage of the signal output terminal to a pull-low control terminal. The discharging circuit turns on when a voltage of the pull-low control terminal is larger than a predetermined voltage level to discharge the switch control terminal to pull the switch control terminal to a second high level voltage. A second voltage pull-low circuit pulls the switch control terminal to a low level voltage when the output terminal voltage is larger than a reference voltage and does not have a glitch.

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Hsinchu, Taiwan

Li-Cheng Chu