Other Parts Discussed in Thread: DRV8412
Hello,
I'd like to get your feedback on a DRV8243 application. This is controlling a Peltier cooler rated for 5.4A continuous. 24V system. For optimal efficiency I need a smooth voltage across the Peltier so I added a fairly large filter at the output of the DRV8243.
Is this part ok at sustained 5.4A current? If Rds,on = 98mA then Pdiss @ 5.4A = 2.857W continuous.
MODE = CONNECT TO GND THROUGH ZERO OHM FOR PH/EN MODE. IN1 IS PWM INPUT, IN2 IS DIRECTION (hot or cold).
SLEW RATE = LVL3 IS 13.3 V/uSEC (22K TO GND) - Is this fine for a PWM based application?
Ipropi = (Ihs1 + Ihs2) / Aipropi
Ihs1 = Ihs2 = 6A (MAX CURRENT OF PELTIER COOLER) -> should this be 6A or 12A? Only one side will be high at once.
Aipropi = 3070A/A
SO Ipropi = 1.95mA
WANT TO SENSE THIS OVER 2.5V ADC INPUT. R = V/I
R = 2.5/0.00195 = 1280 OHM
ITRIP = (Vitrpi/Ripropri) * Aipropri
Vitpri IS SET WITH A RESISTOR: ITRIP (IN AMPS) AT R6OF6 = (2.97 / 1280) * 3070 = 7.12A; BEST
R60F6 = HI-Z (MIN 250K; 1M OK)
DIAG IS INPUT TO DRV8243; ENABLES OFF-STATE DIAGNOSTICS, ALSO CONFIGURES FAULT REACTION
FOR OFF-STATE DIAGNOSTICS ENABLED; FAULT=LATCH; SHOULD BE EITHER R2OF6, R3OF6, R4OF6, OR R5OF6.
DIAG = 22K FOR RLVL3OF6
Filter on the output still needs to be tweaked but based on this:
Thanks,
Derek
