DRV8705-Q1: Driver PWM Issue

sonali zodage

Part Number: DRV8705-Q1

Hello,

We are using DRV8705S motor driver ICs for our application to drive dc motor. We have set the following configuration to control register to drive the motor:

	Name	Address	Value
CONTROL REG	IC_CTRL	4h	0x86
	BRG_CTRL	5h	0x20
	DRV_CTRL_1	6h	0xFF
	DRV_CTRL_2	7h	0xFF
	DRV_CTRL_3	8h	0x24
	VDS_CTRL_1	9h	0x30
	VDS_CTRL_2	Ah	0x00
	OLSC_CTRL	Bh	0x00
	UVOV_CTRL	Ch	0x1C
	CSA_CTRL	Dh	0x01

We have set EN/PH input control mode.

Expected result : Driver will set pwm on GH1 and GL2 pins while GH2 and GL1 pins should be off and vice versa.

Observed result : Driver sets the pwm on GH1 and GL2, inverted pwm of GL2 on GH2 and there is no pwm for GL1.

Can someone indicate on what might be causing this?

Please find attached schematic for your reference.

0066.IO_Controller_Rev3.0_Schematic.pdf

Thanks,

Sonali

over 2 years ago

0 Shinya Morita over 2 years ago

TI__Mastermind 44415 points

Hi,

Thank you for your question.

Based on your register value, you set BRG_MODE = 01 and BRG_FW=0

Therefore GHx/GLx will output as follows. Without your IN1/IN2 input condition, it is difficult to judge your result is correct or not.

I suggest to scope a) IN1/IN2/GH1/GL1, N1/IN2/GH2/GL2 and N1/IN2/SH1/SH2. Then we can compare with above table to confirm.

By the way, you are attaching table for PWM, although you are choosing PH/EN mode. FYI.

Thanks,

regards

Shinya Morita

0 sonali zodage over 2 years ago in reply to Shinya Morita

Intellectual 365 points

Hello Shinya,

We have set above mentioned configurations to control register for both the DRV8705S-Q1 EVM and our custom board and observed the following waveforms.

Waveform observed for DRV8705S Eval Kit :

1) IN1 and IN2 vs GH1 and GL1