Patent ID: 7777555
Filing Date: 2010-08-17
Classification: G05F,H03K

Abstract:
1. A temperature compensating circuit, comprising: a reference circuit having a reference current and a resistance circuit, wherein the resistance circuit has a first terminal receiving the reference current, a second terminal and a negative-temperature-coefficient resistor, and at least a first portion of the reference current flows through the negative temperature coefficient resistor; a first transistor having a drain, a source, a gate and a path disposed between the drain and the source, wherein the path of the first transistor is connected in series with the resistance circuit, the gate of the first transistor is electrically connected to the drain of the first transistor and the second terminal of the resistance circuit, and the drain of the first transistor produces a first bias-voltage signal; a second transistor electrically connected to the first transistor and having a drain; and a ring oscillator producing a first output signal having an oscillation frequency in response to the first bias-voltage signal, and including an inverter circuit producing a second output signal in response to the first output signal and the first bias-voltage signal, wherein: the first and the second transistors constitute a current mirror; the drain of the second transistor produces a first current; and the temperature compensating circuit utilizes the negative-temperature-coefficient resistor to compensate the first current for a temperature change in the temperature compensating circuit.