Richtek Technology Corporation

Summit Microelectronics, Inc.

Xiaoyong Zhang

Jing-Meng Liu

Chiawei Liao

Takashi Kanamori

The present invention discloses a backlight control circuit capable of distinguishing an under current condition, comprising: at least one light emission device path having a voltage node; at least one current source for controlling the current amount on the light emission device path; and at least one under current detection circuit for generating a first control signal according to the voltage at the voltage node, wherein when the first control signal changes its state, the under current detection circuit generates a second control signal to change the voltage on the voltage node if the light emission device path is normally connected.

Backlight control circuit capable of distinguishing under current condition

In one embodiment the present invention includes an over-current protection method. The method comprises generating a switching signal, starting and stopping a timer, sensing a current through a switch, comparing a response time to a reference time, and generating an over-current alarm signal. The switching signal activates one or more switches in a switching regulator. The timer is started in response to the switch being activated and is stopped in response to the sensed current exceeding a threshold. The response time indicates the time period between the starting and the stopping of the timer. The over-current alarm signal is generated if the response time is less than the reference time.

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San Jose, CA, United States of America

Xiaoyong Zhang