VCC LEVEL DETECTION CIRCUIT

摘要

A supply voltage detect circuit is described which generates a control signal indicating the status of VCC to be at 5.0 or 3.3 volts. This control signal is used to generate analog reference signals used by A/D and/or D/A circuitry in an audio processing integrated circuit and by other circuitry to control clock frequencies or current drive. An input buffer is also described which is configurable depending on whether a 5.0 or 3.3 volt supply voltage is present. The input buffer includes two input buffer circuits. The output of a first input buffer circuit is output as valid data when VCC equals 5.0 volts. The output of the second input buffer circuit is output as valid data when VCC equals 3.3 volts.