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TPS82140: PSM/PWM Crossover Frequency when used in Buck/Boost (Inverting) Configuration

Part Number: TPS82140
Other Parts Discussed in Thread: TIDA-01457

Hello,

I'm trying to figure out the PSM/PWM crossover frequency of the TPS82140 when used in an inverting buck/boost configuration similar to TIDA-01457.   

My design parameters are: VIN = 3.3V (fixed), VOUT = -6V.    Using equations 2/3 from TIDA-01457, I calculated a duty cycle of 64.5% and a inductor ripple current of ~1.06A.   Per page 8 of the TPS82140 datasheet, the device enters PSM mode when the output current is equal to half of the inductor ripple current; which in this case is ~500mA.

This seems to line up with figure 14 in TIDA-01457; however, I'd like a second opinion on this.

Don