请教RCD钳压电路的设计公式的一个疑问？

miklystone

Figure 3. MOSFET turn-off waveforms with clamping.

This implies that the power dissipated in the clamp at turn-off is

PCLAMP = (1/2) × VCLAMP × ICLAMP × ∆t × f

Where, f is the switching frequency.

However,

∆t = (LLP × IP)/(VCLAMP - VOUT/N).

The power dissipated in the clamp is through the resistor. Therefore

RCLAMP = [2 × VCLAMP × (VCLAMP - VOUT/N)]/( LLP × IP² × f) (a)

It is important to minimize the ripple, Vripple, superimposed on VCLAMP to keep the MOSFET drain voltage close to
the clamp voltage. The minimum value for the capacitor, CCLAMP, is therefore CCLAMP = VCLAMP/ (Vripple × RCLAMP
× f

我想问公式（a）怎么理解，我理解是漏感电压的能量会在电阻上消耗掉，但是为什么电阻上消耗的功率那样计算的...我看的raidly也是这样写得，但是我没理解到，请大侠解释下...
参考资料：maxim AN848