Abstract: A random code generating method for the magnetoresistive random access memory is provided. Firstly, a first magnetoresistive random access memory cell and a second magnetoresistive random access memory cell are programmed into an anti-parallel state. Then, an initial value of a control current is set. Then, an enroll action is performed on the first and second magnetoresistive random access memory cells. If the first and second magnetoresistive random access memory cells fail to pass the verification action, the control current is increased by a current increment, and the step of setting the control current is performed again. If the first and second magnetoresistive random access memory cells pass the verification action, a one-bit random code is stored in the first magnetoresistive random access memory cell or the second magnetoresistive random access memory cell.

Abstract: A switch device includes a P-type substrate, a first gate structure, a first N-well, a shallow trench isolation structure, a first P-well, a second gate structure, a first N-type doped region, a second P-well, and a second N-type doped region. The first N-well is formed in the P-type substrate and partly under the first gate structure. The shallow trench isolation structure is formed in the first N-well and under the first gate structure. The first P-well is formed in the P-type substrate and under the first gate structure. The first N-type doped region is formed in the P-type substrate and between the first gate structure and the second gate structure. The second P-well is formed in the P-type substrate and under the second gate structure. The second N-type doped region is formed in the second P-well and partly under the second gate structure.

Abstract: A filter circuit comprises a resistor-capacitor (RC) circuit, a comparator circuit, and an output control circuit. The RC circuit is configured to generate a ripple voltage according to the PWM signal. The comparator circuit couples with the RC circuit, and is configured to compare the ripple voltage with a first reference voltage, and output a switch signal according to a comparison result. The output control circuit couples with the comparator circuit and the RC circuit, and is configured to generate an output signal according to the switch signal and the PWM signal. When a duty ratio of the PWM signal is larger than a predetermined threshold value, the output signal is corresponding to the PWM signal. When the duty ratio of the PWM signal is smaller than the predetermined threshold value, the output signal is not corresponding to the PWM signal.

Abstract: A filter circuit comprises a resistor-capacitor (RC) circuit, a comparator circuit, and an output control circuit. The RC circuit is configured to generate a ripple voltage according to the PWM signal. The comparator circuit couples with the RC circuit, and is configured to compare the ripple voltage with a first reference voltage, and output a switch signal according to a comparison result. The output control circuit couples with the comparator circuit and the RC circuit, and is configured to generate an output signal according to the switch signal and the PWM signal. When a duty ratio of the PWM signal is larger than a predetermined threshold value, the output signal is corresponding to the PWM signal. When the duty ratio of the PWM signal is smaller than the predetermined threshold value, the output signal is not corresponding to the PWM signal.