TLE92108 Not Driving Motors As Expected

[CMG_Engineer]

I am trying to statically drive motors using the TLE92108 and SiZ342ADT transistors, but the motors being driven are not matching the HBMODE that I am commanding. It appears to be an issue of the transistors not being turned off when the HB is in high impedance.

I am driving six motors with the following configuration

• Motor 1 - HB1 and HB2
• Motor 2 - HB2 and HB3
• Motor 3 - HB3 and HB4
• Motor 4 - HB5 and HB6
• Motor 5 - HB6 and HB7
• Motor 6 - HB7 and HB8

HB1 - HB4 share a common drain and HB5 - HB8 share another common drain. Both drain voltages are 12.2V.

Since the behavior experienced on motors 1-3 is the same as what I experienced with motors 4-6, I will just be talking about the first three motors.

When trying to drive motor 1, only motor 1 is driven. When trying to drive motor 2, all three motors are driven and moving slowly. Attempting to move motor 3 fails and the high side HB has an overvoltage error. It seems like when the unused HB should be in high impedance, the gates transistors are not turned off. Below are the voltages measured in each HBMODE combination.

	Motor 1		Motor2		Motor 3
HBMODE	0x0006	0x0009	0x0042	0x0081	0x0060	0x0090
HB1 (V)	12.2	0	12.2	0
HB2 (V)	0	12.2	6.1	6.1
HB3 (V)	0	12.2	2.8	9.3
HB4 (V)	0	12.2	0	12.2
HB5 (V)	12.7	12.7	12.7	12.7
HB6 (V)	12.7	12.7	12.7	12.7
HB7 (V)	12.7	12.7	12.7	12.7
HB8 (V)	12.7	12.7	12.7	12.7

This behavior exists and the voltages are the same when BD_PASS = 0 and 1.

The attached image shows the arrangement of the half-bridge transistors. The gate pins connect directly to the TLE9210X, i.e. no resistors in series or tied to ground.

Any help resolving this is greatly appreciated.

[Vinay · Accepted solution]

Hi @CMG_Engineer,

Good Day!

Thanks for posting your question in the Infineon community.

Could you share us the details about how you are configuring the gate pulses in Multi Mosfet driver?

The below explanation is with respect Config wizard GUI for Multi Mosfet driver.

Motor M1 is connected between HB1 and HB2, Motor M2 is connected between HB2 and HB3 and Motor M3 is connected between HB3 and HB4.

Modes:

High Impedance mode: All the switches are Open.

PWM is mapped to HB1

HS1/LS2 --> HS1 is ON for Duty Cycle times, LS1 is ON for (1-Duty Cycle times).

LS2 is completely ON for freewheeling and HS2 is completely OFF.

SH1 is HIGH for Duty cycle times and SH2 is totally LOW as LS2 is completely ON.

LS1/HS2 --> LS1 is ON for Duty Cycle times, HS2 is ON for (1-Duty Cycle times).

HS2 is completely ON for freewheeling and LS2 is completely OFF.

SH1 is HIGH for (1-Duty cycle times) and SH2 is totally HIGH as HS2 is completely ON.

PWM is mapped to HB2

HS1/LS2 --> HS1 is completely ON for freewheeling and LS1 is completely OFF.

HS2 is ON for (1-Duty Cycle times), LS2 is ON for Duty Cycle times.

SH1 is totally HIGH as HS1 is completely ON and SH2 is HIGH for (1-Duty cycle times).

LS1/HS2 --> HS1 is completely OFF and LS1 is completely ON for freewheeling.

HS2 is ON for Duty Cycle times, LS2 is ON for (1-Duty Cycle times).

SH1 is totally LOW as LS1 is completely ON and SH2 is HIGH for Duty cycle times.

You can control Motor M1 alone by mapping PWM to HB1 or HB2, similarly you can control Motor M3 alone by mapping PWM to HB3 or HB4. But Motor M2 is connected between HB2 and HB3, so while controlling Motor M2, the motors M1, and M3 shall also run since PWMs shall be mapped to HB1 or HB2 and HB3 or HB4.

Could you share the PWM mapping with Half bridges?

Thank you!

[CMG_Engineer]

Thanks for the reply.

I rearranged how the motors are attached and I am now having drain source over voltage errors. Since that's a different issue, I've made a new post. Thanks.