Circuit for providing low-noise band-gap reference voltage source

Abstract

The invention provides a circuit for providing a low-noise band-gap reference voltage source. The band-gap reference voltage source provides multiple circuits of current with temperature coefficients, and the temperature coefficient of the current can just counteract the temperature coefficient of a resistance adopted in the reference voltage source. The band-gap reference voltage source with zero temperature is generated when the current flows by the resistance, and a low-pass filter with low cut-off frequency is connected behind the band-gap reference voltage source to filter the noise of the band-gap reference voltage source, so that different current can be supplied to different modules in a radio frequency (RF) chip on a subscriber identity module (SIM) card of a mobile phone.

Description

technical field [0001] The invention relates to the field of bandgap reference voltage sources, in particular to a low-noise bandgap reference voltage source. Background technique [0002] The radio frequency RF chip needs to provide a low-noise bandgap reference voltage source for the radio frequency RF module, and it is not allowed to interfere with the low-noise bandgap reference voltage source when each module is working. The traditional method is to plug a large capacitance. Filter the bandgap reference with a bulk capacitor. [0003] However, there are the following problems in filtering the bandgap reference voltage source with a general external large capacitor: [0004] (1) It is necessary to add a large capacitor outside the chip, which adds a capacitor cost to the whole solution, and needs to add a capacitor area on the PCB (Printed circuit board) board. At the same time, the external capacitor requires one more chip pin on the chip, which increases the cost of...

AI Technical Summary

Problems solved by technology

[0004] (1) It is necessary to add a large capacitor outside the chip, which adds a capacitor cost to the whole solution, and needs to add a capacitor area on the PCB (Printed circuit board) board

At the same time, the external capacitor requires one more chip pin on the chip, which increases the cost of a bonding wire to the chip.

[0005] (2) Since there are many RF modules that need to use a low-noise bandgap reference voltage source in the RF chip, but the bandgap reference voltage source can only be connected with an off-chip capacitor, all RF modules that need to use a low-noise bandgap voltage reference source Modules must share a low noise bandgap reference

[0006] (3) The external capacitance of the bandgap reference voltage source will cause the problem of too long start-up time of the bandgap reference voltage source, which will bring the overhead of the entire system start-up time

Images