Hi, I have the MPQ5031 paired with the MPQ4214 to make a USB PD charger. In isolation the 4214 is happy to buck the input voltage (35V) down to 5V, 9V…. 20V - all at 5A, so the power supply is working nicely.
When I connect a device (or the PM125 USB PD Tester) then I can see the CC line communications taking place while the 5031 and the sink negotiate PDOs. Then I see the i2c communications between the 5031 and the 4214. The 5031 sets the VREF to 400mV and ILIM to 0x111 and I see the power supply wake up. It then reads the interrupt status register and clears it. Then about 500ms later, the 5031 issues a hard-reset over the CC line and everything restarts. It is stuck in this loop permanently.
I am not seeing the PS-RDY message at any time on the CC line. VBUS is good, and connected to pin 20 of the 5031 (in fact I’ve nudged it up to 5.2V in case it was borderline).
What else would prevent the PS-RDY message being issued, and/or what else might be causing the repeating hard-reset after PDO negotiation?
It has this same behaviour with a regular mobile phone, as well as the PM125 tester. I’ve tried setting different values on the PDOs, and enabling and disabling them all.
Out of the 5031 I have the GPIO configured as:
GPIO1 = INT, connected to the 4214 INT output
GPIO2 = PWR_SHARE, connected to my uC but set high at the moment.
GPIO3 = ISENS+, connected to the 4214 COMP pin
GPIO4 = NTC2, connected to my uC but set high at the moment
GPIO5 = IPWM, connected to the 4214 PWM input
GPIO6 = EN, connected to resistor divider off of Vin to come on after the 4214 - also open collector under uC control if needed
GPIO7= ADJ, connected to the 4214 FB pin to add a 2uA pull down when output is under load.
I’m hoping somebody can help