A hall detecting and amplifying system, comprising:
- a signal amplifying system, comprising:
- 1) an oscillator, comprising a first resistor with a first resistance R1 and a first capacitor with a first capacitance C1, the oscillator is configured to provide an oscillating signal having a frequency f, wherein f=k1/(R1*C1), where k1 is a first proportional parameter;
- and
- 2) an amplifying circuit configured to receive the oscillating signal and an input signal, and further configured to amplify the input signal under the control of the oscillating signal, the amplifying circuit comprises a bias circuit having a second resistor with a second resistance R2, and an amplifying potion having a second capacitor with a second capacitance C2, the amplifying circuit has a −3 dB bandwidth W−3 dB_Amp, wherein W−3 dB_Amp=k2/(R2*C2), where k2 is a second proportional parameter;
- wherein the product of the first resistance R1 and the first capacitance C1 is proportional to the product of the second resistance R2 and the second capacitance C2;
- a first transistor having a first terminal, a second terminal and a control terminal, wherein the first terminal is configured to receive a hall bias current, the control terminal is configured to receive the complementary signal of the oscillating signal;
- a second transistor having a first terminal, a second terminal and a control terminal, wherein the first terminal is configured to receive the hall bias current, the control terminal is configured to receive the oscillating signal;
- a third transistor having a first terminal, a second terminal and a control terminal, wherein the second terminal is coupled to a reference ground, the control terminal is configured to receive the complementary signal of the oscillating signal;
- a fourth transistor having a first terminal, a second terminal and a control terminal, wherein the second terminal is coupled to the reference ground, the control terminal is configured to receive the oscillating signal;
- a fifth transistor having a first terminal coupled to the input terminal of the amplifying circuit, a second terminal coupled to the second terminal of the second transistor, and a control terminal configured to receive the oscillating signal;
- a sixth transistor having a first terminal coupled to the input terminal of the amplifying circuit, a second terminal coupled to the second terminal of the first transistor, and a control terminal configured to receive the complementary signal of the oscillating signal;
- a seventh transistor having a first terminal coupled to the input terminal of the amplifying circuit, a second terminal coupled to the first terminal of the third transistor and a control terminal configured to receive the oscillating signal;
- an eighth transistor having a first terminal coupled to the input terminal of the amplifying circuit, a second terminal coupled to the first terminal of the fourth transistor, and a control terminal configured to receive the complementary signal of the oscillating signal;
- and
- a hall sensor having a first contact coupled to the second terminal of the second transistor, a second contact coupled to the first terminal of the third transistor, a third contact coupled to the first terminal of the fourth transistor and a fourth contact coupled to the second terminal of the first transistor.