US Patent No. 9,134,349

AMPLIFIER CIRCUITS AND METHODS


Patent No. 9,134,349
Issue Date September 15, 2015
Title Amplifier Circuits And Methods
Inventorship Jinxi Hu, Shanghai (CN)
Jiabin Wang, Shanghai (CN)
Xujiang Huang, Shanghai (CN)
Assignee BCD Semiconductor Manufacturing Limited, Shanghai (CN)

Claim of US Patent No. 9,134,349

1. A chopper amplifier circuit for sensing Hall voltage, the amplifier circuit comprising:
a Hall sampling circuit, including a first switching circuit for selectively coupling each of four nodes of a Hall plate to
either a power source or a ground terminal;

a differential amplifier;
a second switching circuit configured for selectively coupling each of the four nodes of the plate to inputs of the differential
amplifier;

a Hall voltage signal retaining circuit, including a first group of four storage devices and a second group of four storage
devices;

a third switching circuit configured for storing a first output of the differential amplifier to one of the first group of
four storage devices and for storing a second output of the differential amplifier to one of the second group of four storage
devices; and

a fourth switching circuit configured for selectively coupling the first group of four storage devices to a first output of
the chopper amplifier circuit and for coupling the second group of four storage devices to a second output of the chopper
amplifier circuit.