A Low Noise, High Stability Infrared Bias Power Supply

Abstract

The invention relates to a low-noise and high-stability infrared bias power supply which consists of two parts including a triple voltage circuit and a voltage stabilization filter unit circuit, wherein the triple voltage circuit comprises a pre-voltage stabilizing circuit, an oscillation circuit, a shaping circuit and a push-pull and triple voltage circuit; after power is input into the pre-voltage stabilizing circuit, the power voltage with stable amplitude is output and is stably provided for other circuits in the triple voltage circuit; the oscillation circuit is used for generating signals with fixed frequency and outputting the signals into the shaping circuit; the shaping circuit is used for shaping the signals, and the signals are changed into regular square signals; the push-pull and triple voltage circuit is used for carrying out push-pull output and triple boosting on the square signals; the voltage stabilization filter unit circuit is used for generating a stable reference source and converting the voltage which is output by the push-pull and triple voltage circuit and boosted by three times into the voltage needed by an infrared detector by utilizing the generated reference source.

Description

technical field [0001] The infrared bias power supply involved in the invention provides the required working bias voltage for the thermistor type infrared detector used in the infrared earth sensor. Background technique [0002] The infrared bias power supply provides the required working bias voltage for the thermistor type infrared detector. The infrared bias power supply essentially provides a high-precision reference source for the infrared detector. In order to achieve high detection accuracy, the infrared bias power supply is required to have a low noise level (generally, the root mean square value is required to be below 1μV) and stable Degree (Generally, the voltage temperature stability is required to be less than 0.1mV / ℃.). [0003] The existing infrared bias power supply adopts the design scheme of DC / DC power supply, the input circuit adopts the scheme of push-pull self-excited DC converter to drive the power switch chip, and generates a rectangular wave voltag...

AI Technical Summary

Problems solved by technology

In this scheme, the generation of ±20V power supply is realized by LM117H and LM137H. Since LM117H and LM137H are commonly used linear voltage regulator chips, they have no noise index, and the measured noise root mean square value is about 25μV, which cannot meet the requirements of the product.

Generally, multi-stage filtering is used at the output of the infrared bias power supply to reduce noise, but low-frequency 1 / f noise is difficult to filter out, which cannot meet the requirements of high-precision detection

This design method makes the circuit structure complex, noisy and low reliability

Images