A circuit for improving adc sampling precision

Abstract

The invention provides a circuit for improving ADC sampling accuracy, and the cathode voltage from a transmitter is received. The circuit comprises a capacitance-resistance voltage divider circuit (1), an operational amplifier circuit (2), a first resistor (3), a rectifier diode (4), a zener diode (5), and an instrumentation amplifier circuit (6). The capacitance-resistance voltage divider circuit (1) and one end of the operational amplifier circuit (2) are connected in series, the other end of the operational amplifier circuit (2) is connected to the first resistor (3) in series, at the same time, the first resistor (1) is also orderly connected to the rectifier diode (4) and the zener diode (5) in series, two ends of the first resistor (3) are connected to the instrumentation amplifier circuit (6) in parallel, and the value of voltage which passes the instrumentation amplifier circuit (6) is sampled. According to the circuit for improving ADC sampling accuracy, through a capacitance-resistance device parameter and a zener diode parameter, the interception ratio of the sampling voltage can be conveniently adjusted, the raised multiple of sampling precision is set, and the circuit has high generality and can be applied in many sampling circuits.

Description

technical field [0001] The invention belongs to the technical field of digital power supplies, is particularly suitable for high-voltage power supplies of transmitters, relates to the design and application of high-voltage electric vacuum transmitters, and specifically relates to a circuit for improving sampling accuracy of ADCs. Background technique [0002] With the rapid development of electronic devices such as DSP, switching power supplies are moving towards digitalization. In order to achieve a good voltage regulation closed-loop control, it is necessary to sample the output voltage to obtain the current voltage value, and the digital power supply must use analog-to-digital conversion to achieve this step. In terms of performance, the current AD conversion accuracy is limited, and the actual effect is slightly lower than the nominal conversion accuracy; in terms of application cost, the higher the accuracy of the AD converter, the more expensive the chip, and the highe...

AI Technical Summary

Problems solved by technology

If in order to reduce the cost, still only use the ordinary precision AD converter to collect the divided voltage sampling value, the sampling accuracy is not high under some application conditions, especially in the field of high voltage power supply, which will eventually lead to an increase in the steady state error and even cause oscillation

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