Patent ID: 7816976
Filing Date: 2010-10-19
Classification: G05F

Abstract:
1. A power supply circuit, comprising: a reference voltage generation circuit; a power supply voltage generation circuit to receive a first reference voltage from the reference voltage generation circuit, the power supply voltage generation circuit boosting the first reference voltage to generate a boosted power supply voltage; and a bandgap reference circuit to receive the boosted power supply voltage so as to generate a second reference voltage by using the boosted power supply voltage, wherein the reference voltage generation circuit is provided with first and second P-channel transistors, first to fourth N-channel transistors, and first to third resistors, the first P-channel transistor has a source connected to a first higher voltage supply, the second P-channel transistor has a source connected to the first higher voltage supply, a gate of the second P-channel transistor is connected to a drain of the second P-channel transistor and a gate of the first P-channel transistor, a drain of the first N-channel transistor is connected to a drain of the first P-channel transistor, a gate of the first N-channel transistor is connected to the drain of the first N-channel transistor, a gate of the second N-channel transistor is connected to the gate of the first N-channel transistor, a drain of the second N-channel transistor is connected to the drain of the second P-channel transistor, one end of the first resistor is connected to a source of the first N-channel transistor, the first resistor has the other end connected to a lower voltage supply, a drain of the third N-channel transistor is connected to a source of the first N-channel transistor, a gate of the third N-channel transistor is connected to a drain of the third N-channel transistor, the third N-channel transistor has a source to connect to the lower voltage supply, a threshold voltage of the third N-channel transistor is lower than each of the threshold voltages of the first and second N-channel transistors, one end of the second resistor is connected to a source of the second N-channel transistor, the second resistor has the other end to connect to the lower voltage supply, one end of the third resistor is connected to the source of the second N-channel transistor, a drain of the fourth N-channel transistor is connected to the other end of the third resistor, a gate of the fourth N-channel transistor is connected to the drain of the fourth N-channel transistor, the fourth N-channel transistor has a source connected to the lower voltage supply, and a threshold voltage of the fourth N-channel transistor is lower than each of the threshold voltages of the first and second N-channel transistors.