Patent ID: 7436244
Filing Date: 2008-10-14
Classification: G05F

Abstract:
1. A circuit for reference current and voltage generation, comprising: a current bias circuit receiving an enable signal, wherein when the enable signal is in an enabling state, the current bias circuit provides a reference current, a bias signal, and a startup signal, and when the enable signal is in a disabling state, the current bias circuit provides a first predetermined voltage and a second predetermined voltage; and a voltage reference circuit electrically coupled to the current bias circuit, wherein the voltage reference circuit enters into a turned-on state and provides a reference voltage after receiving the bias signal and the startup signal, and enters into a turned-off state after receiving the first predetermined voltage and the second predetermined voltage; wherein the current bias circuit further comprises: a startup circuit receiving a state signal and outputting the startup signal when the state signal is in a turned-off state; a first isolator receiving the enable signal and receiving the startup signal from the startup circuit, wherein when the enable signal is in the enabling state, the first isolator provides the startup signal, and when the enable signal is in the disabling state, the first isolator provides a third predetermined voltage; a constant gm bias circuit electrically coupled to the first isolator and providing the state signal to the startup circuit according to a state of the constant gm bias circuit, wherein the constant gm bias circuit enters into the turned-on state and provides the reference current and the bias signal after receiving the startup signal from the first isolator, and enters into the turned-off state after receiving the third predetermined voltage from the first isolator; and a second isolator receiving the enable signal, wherein when the enable signal is in the enabling state, the second isolator transmits the bias signal provided by the constant gm bias circuit to the voltage reference circuit and transmits the startup signal provided by the first isolator to the voltage reference circuit, whereas when the enable signal is in the disabling state, the second isolator provides the first predetermined voltage and the second predetermined voltage to the voltage reference circuit.