Microcontroller With Average Current Measurement Circuit Using Voltage-To-Current Converters

摘要

The average of a complex waveform measured over a time period may be determined by first converting the complex waveform to a voltage, then converting this voltage to a current and using this current to charge a capacitor. At the end of the measurement time period the voltage charge (sample voltage) on the capacitor may be sampled by a sample and hold circuit associated with an analog-to-digital converter (ADC). Then the voltage charge on the sample capacitor may be removed, e.g., capacitor plates shorted by a dump switch in preparation for the next average of the complex waveform sample measurement cycle. The ADC then converts this sampled voltage charge to a digital representation thereof and a true average of the complex waveform may be determined, e.g., calculated therefrom in combination with the measurement time period.

主权项

1. A microcontroller, comprising:
an external connection configured to receive a voltage; a voltage-to-current converter having an input coupled to the external connection and adapted to convert the voltage to a current, wherein an output of the voltage-to-current converter is coupled to a sample capacitor and the current therefrom charges the sample capacitor to a sample voltage during a measurement time period; an analog-to-digital converter (ADC) configured to be coupled to the sample capacitor after the measurement time period is over, wherein the ADC samples and then converts the sample voltage on the sample capacitor to a digital representation thereof; and a sample voltage reset switch coupled to the sample capacitor, wherein the sample voltage reset switch resets the sample capacitor to a substantially zero voltage after the ADC has sampled the sample voltage thereon.