[SOLVED] TI DRV8838 question - help with use and datasheet info

Hi,

Admin - Please move if posted in wrong section.

I'm intending to build a quick test bench to test a change in a hardware design and count the corresponding action. (The originating piece of kit uses a battery fed 3v DC motor which needs to be regularly reversed)

I don't want to use a PWM due to complexity and to keep the design close to the original as possible.

I intend to use one of the low voltage drivers from TI (DRV883x) range or more specifically DRV 8838. Now looking at the datasheet (combined 8837 & 8838) the 8837 looks to be solely PWM on IN1 & IN2 ???, however the 8838 states PHASE/ENABLE.

I don't fully understand what the datasheet says pertaining to the inputs and PWM, could someone please give the enclosed datasheet a quick once over at see if I am right in thinking the 8838 is the right choice for basic forward / reverse control at fully battery voltage. ENABLED tied high with direction and sleep pulsed as appropriate.

Thanks
Matt

Hi Matt,

the statement on PWM mean that you can drive the IN1/2 with a PWM-signal or a static logic. See table 1 "DRV8837 Device Logic" on how to ally the control inputs for fowward and reverse.

Enjoy your design work!

Regards HTA

Hi HTA,

Thanks for the reply.

Yeah, it was those tables (Tables 1 and Table 2) that have thrown me a bit - if both device's input were logic capable why mention PWM, I don't understand why have two identical devices doing exactly the same and having the same spec. (I'm picturing pulses being fed into theses pins 8837 but logic levels on the 8838)

OK now assuming I have thought too deeply about this - realistically, how would I base a decision on which chip to buy based on the datasheet info when the only difference is the PWM inputs on the 8837?

Thanks
Matt

Hi Matt,

the 8837 can be driven by one PWM signal and one direction control signal on IN1/2. The 8838 is for static control with on/off on the EN input and direction on the PH input(see table 1). A timing diagram for each case would be useful for TI to add.

Enjoy your design work!

Regards HTA