| 摘要 |
PURPOSE: To control measurement of load current by separating it perfectly using a single detection resistor and a single comparator circuit by performing switching control of a current detection circuit. CONSTITUTION: A stepping motor drive circuit comprises a single sense resistor R and a single control circuit including a flip-flop FF being synchronized with a clock signal CLK and controlled through a comparator C for comparing the voltage being applied to the resistor R with a reference voltage Vref. Two AND gates PA, PB are driven by an output signal Q from the flip-flop FF and switches SWA, SWB are controlled by the outputs from the AND gates PA, PB. The AND gates PA, PB prohibit simultaneously conduction of two switches SWA, SWB positively and the resistor R measures only one load current at any time. |
