36 W (72 W Peak) Variable-Speed DC Motor Drive:The fl yback converter shown in Figure 1 uses a member of the PeakSwitch family (U1, a PKS606YN) to drive a 36 W motor, while delivering startup and load transition peaks of up to 72 W. The motor’s speed is variable by two methods: 1) potentiometer R20 (connected to J3), or 2) an externally supplied 3.6 V to 10 VDC voltage source (connected to J4). The motor speed controls vary the output voltage of the supply.