| 摘要 |
PURPOSE:To realize low noise PWM drive in a low power consumption by connecting a fifth active element having the current supply capability lower than that of a first active element between a first operation voltage point and a first terminal in parallel with the first active element. CONSTITUTION:MULX is PWM-driven for obtaining a positive IVCM. Namely, a current is supplied to a load through the loops MULX LVCM, RVCM MDR by setting MDR to ON state and MUR, MDL, MURX to OFF state. When a current reaches a target load current or more, MULX is set to OFF, changing to the circulation current mode of MDL LVCM, RVCM MDR. When a load current becomes lower than the target value, MULX is turned ON again. When MULX is turned OFF, a load current can be supplied since a potential between drain and body of MDL is forward-biased even when MDL is left in the OFF state but since an attenuation time constant of load current is set to a small value, when MULX is turned OFF, it is possible that MDL is turned ON, lowering a voltage drop at MDL. |
