Holtek Microelectronics Inc.

Kuo-Cheng Yu

Jason Chen

Ching-Yi Lin

Yi Lin

Bao-Shiang Sun

A voltage detector circuit for instantaneously detecting abnormal voltages in a micro controller includes a voltage detection circuit connected between the power supply and reset voltage ends of an internal circuit of the micro controller so as to instantaneously detect changes in the power supply, without the time delay associated with the external low pass filter that supplies the reset voltage. The detecting circuit is a logic 'NOT' gate which has a power supply connecting end connected to a reset voltage end of the internal circuit, an input end connected to the power supply end of the internal circuit, and an output end connected to a cooperating input end of the latch circuit, so that the latch circuit latches a signal output by the voltage detector whenever an abnormal power supply voltage is detected, and outputs a flag signal to the micro controller to effect an instantaneous reset of the micro controller. The latch may be a flip-flop, in which case one of the flip-flop inputs is connected to the voltage detector output and the other input may be connected together with the flip-flop power supply input to the reset voltage, the flip-flop providing two outputs, one of which may be connected to the micro controller reset pin, and the other of which may be connected to an interrupt or other indicator device.

Means for instantaneously detecting abnormal voltage in a micro

A timer which provides both the surveying and counting functions. It contains a counter, a multiplexer, an edge-triggered controller, a time-base latching circuit, and a pulse-detecting circuit. It not only can be used as a timer, but can also be used as a counter to count the number of the external signals so as to detect the width of an external signal.

Timer that provides both surveying and counting functions

The present invention relates to a reset signal generator adapted to be used with a microprocessor for generating a reset signal to initialize the microprocessor, which includes an oscillator to generate a fixed clock signal, a counter electrically connected to the oscillator for generating a cyclic signal in response to the fixed clock signal and outputting the reset signal at an end of a period of the cyclic signal, and a clear signal generating device electrically connected to the counter and outputting a clear signal for the counter in response to an output signal from the microprocessor. The present invention ensures that when the microprocessor is abnormal or down it will be initialized by the reset signal.

Growing community of inventors

Hsinchu, Taiwan

Kuo-Cheng Yu