Abstract: An exemplary embodiment of the present invention is an A/D conversion device including: a sample-and-hold circuit that holds an analog input voltage; a sequential conversion register that stores a digital value corresponding to a threshold; a D/A converter that generates an analog voltage corresponding to the digital value stored in the sequential conversion register; a comparator that compares an analog voltage output from the sample-and-hold circuit with an analog voltage obtained from the D/A converter, and outputs a comparison result; a comparison result counter that outputs a determination result according to a count number counted based on the comparison result; and a control circuit that performs control for switching from the comparator function to the A/D conversion function, based on the determination result. During operation of the A/D conversion function, the sequential conversion register sequentially converts the analog voltage held in the sample-and-hold circuit into a digital value.

Abstract: A controller for an induction motor includes a storage device which stores values in a plurality of addresses, a first counter which transits circularly among first to N-th states, a second counter which transits circularly among first to fourth states, a calculating section which calculates calculation values, and a signal generation section which generates PWM signals and synchronous interruption signals at constant time pitch such that pulse widths of the PWM signals are adjusted based on the calculation values respectively. An inverter supplies electric power to an induction motor based on the PWM signals. The first counter transits from one to next of the first to N-th states synchronously to each of the synchronous interruption signals. The second counter transits from one to next of the first to fourth states synchronously to each transition of the first counter from the N-th state to the first state.

Abstract: An exemplary embodiment of the present invention is an A/D conversion device including: a sample-and-hold circuit that holds an analog input voltage; a sequential conversion register that stores a digital value corresponding to a threshold; a D/A converter that generates an analog voltage corresponding to the digital value stored in the sequential conversion register; a comparator that compares an analog voltage output from the sample-and-hold circuit with an analog voltage obtained from the D/A converter, and outputs a comparison result; a comparison result counter that outputs a determination result according to a count number counted based on the comparison result; and a control circuit that performs control for switching from the comparator function to the A/D conversion function, based on the determination result. During operation of the A/D conversion function, the sequential conversion register sequentially converts the analog voltage held in the sample-and-hold circuit into a digital value.

Abstract: A controller for an induction motor includes a storage device which stores values in a plurality of addresses, a first counter which transits circularly among first to N-th states, a second counter which transits circularly among first to fourth states, a calculating section which calculates calculation values, and a signal generation section which generates PWM signals and synchronous interruption signals at constant time pitch such that pulse widths of the PWM signals are adjusted based on the calculation values respectively. An inverter supplies electric power to an induction motor based on the PWM signals. The first counter transits from one to next of the first to N-th states synchronously to each of the synchronous interruption signals. The second counter transits from one to next of the first to fourth states synchronously to each transition of the first counter from the N-th state to the first state.