DRV120: DRV120: What is the minimun PWM OSC freq.

Part Number:DRV120

The fluid valves I'm using have a 24VDC solenoid, 150ohm, 110mH@10kz. I've slowed the PWM clock to ~5KHz (1Meg resistor) to get them to work. Faster PWM clock, say 20KHz does not work at all, the solennoid cycles off and on in a random way. At 10KHz the valve works and sings rather clearly. At 5KHz the singing is reasonable and the valve works, the output waveform looks good.

Rhold =100k

Rpeak =100k

Ckeep=1uf

Vin=24VDC

Rosc=1Meg

So what is minimum frequency the PWM section do tolerate.

this image just before the end of keep time...