Shanghai Xinlong Semiconductor Technology Co., Ltd.

Wei Chi

Bin Liu

Ruiping Li

Jinlong Xu

Jianhu Wang

A short-circuit protection circuit, chip and system for a switched-mode power supply are disclosed. The short-circuit protection circuit includes: a sampling module for sampling an input voltage and producing a first voltage from the input voltage; a generation module for generating a second voltage from a reference voltage; a comparison module for comparing the first voltage and the second voltage; and an output module for producing, from a result of the comparison performed by the comparison module, and outputting a control signal for controlling an external power transistor in the event of a short circuit in the switched-mode power supply. According to the present invention, when an output short circuit is detected, a hiccup-mode duty cycle is adjusted according to the input voltage, thus avoiding great energy loss when the input voltage is high and enabling loaded startup or automatic output recovery after the short circuit condition is removed when the input voltage is low.

Short-circuit protection circuit, chip and system for switched-mode power supply

A current limit control circuit and a switched-mode power supply chip incorporating the current limit control circuit are disclosed. The current limit control circuit includes an output current sampling module, a first voltage comparator module, a hysteresis comparator module, a logic control module, a capacitor charging/discharging module and a current limit control module. The capacitor charging/discharging module is configured to charge/discharge a capacitor and thus change its output voltage, and the hysteresis comparator module is configured to produce a current limit control signal which allows the switched-mode power supply to output a high current for a specified period of time. Upon elapse of the period, the power transistor is controlled to cause a low current to be output. This ensures that the demand of a load for a transient current is satisfied while ensuring safe and stable operation of the chip for a long time.

Current limit control circuit and switched-mode power supply chip incorporating same

A decoding circuit and a chip are disclosed. The decoding circuit includes, connected in a sequence, a charge/discharge unit, a capacitor and a conversion unit. The charge/discharge unit is able to charge and discharge the capacitor, and a ratio of a total time required to transfer any amount of charge into the capacitor to a total time required to transfer the same amount of charge from the capacitor is a predetermined value. The conversion unit is configured to output a third level when a voltage on the capacitor exceeds a predetermined voltage and to otherwise output a fourth level. This arrangement alleviates the computational burden of an MCU, eliminates any adverse effect of noise in a transmitted signal, allows an extended effective transmission distance when using an HBS protocol and is self-adaptive to signals transmitted at different clock rates, thus solving the problems with the prior art including heavy MCU computational burden, a tradeoff between error correction and transmission distance and insufficient adaptiveness to signals transmitted at different clock rates.

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Shanghai, China

Wei Chi