Bias-starving circuit with precision monitoring loop for voltage regulators with enhanced stability
A regulator circuit includes a voltage regulator having a stability control input and an output for providing a regulated output voltage, an amplifier circuit having an input for receiving an error voltage of the voltage regulator, and an output, and a control circuit having an input coupled to the output of the amplifier and an output coupled to the stability control input of the voltage regulator, such that the regulator stability is maximized while the error voltage is minimized. The voltage regulator includes an LDO voltage regulator, the amplifier circuit includes an operational amplifier circuit, and the control circuit includes a load-sensing or load-replicating circuit.
1. A regulator circuit system comprising:
a voltage regulator portion comprising a stability control input, a voltage output configured to provide a regulated output voltage, a voltage regulator output current, an active feedback loop, a first voltage input configured to receive an external reference voltage, and a second voltage input configured to receive a feedback voltage, wherein the difference between the external reference voltage and the feedback voltage defines an error voltage;
an amplifier circuit portion comprising an operational amplifier, the operational amplifier comprising an error voltage input and an amplifier circuit output, wherein the error voltage input is configured to receive the error voltage of the voltage regulator portion; and
a control circuit portion comprising a frequency-to-current converter, wherein the amplifier circuit output is an input to the frequency-to-current converter, and wherein an output of the frequency-to-current converter is coupled to the stability control input of the voltage regulator portion, such that regulator stability is maximized while the error voltage is minimized,
wherein the amplifier circuit portion is configured to amplify the error voltage to provide either a modified reference voltage to the control circuit portion or a correction current to the stability control input of the voltage regulator portion.
2. The regulator circuit system as in claim 1 wherein the voltage regulator portion comprises a low-drop out (LDO) voltage regulator.