Power ManagementのトピックRe: Unexpected BAL_SWITCH_STAT Register Values on MC33774A

Unexpected BAL_SWITCH_STAT Register Values on MC33774A

MarkFan — Mon, 01 Sep 2025 05:37:16 GMT

Hello,

I am working with the MC33774 and have encountered unexpected results when configuring the balancing switch monitor.

Configuration:
- Register: MC33774_BAL_SWITCH_MON_CFG0_OFFSET (0x1006)
- Value written: 0x1F
Observation:
When I read back from the status registers:
- MC33774_BAL_SWITCH_STAT0_OFFSET (0x1010) → returns 0xAAAA or 0x5555
These values are different from what I expected (e.g., 0x15 or 0xA0).

Question:
Could you please clarify why the status registers return 0xAAAA and 0x5555 instead of reflecting the configured value? Is this the correct behavior, or am I missing a step in the configuration procedure?

Thank you for your support.

Mark

Re: Unexpected BAL_SWITCH_STAT Register Values on MC33774A

TomasVaverka — Mon, 01 Sep 2025 06:57:23 GMT

Hello Mark,

These returned values are expected and reflect the real-time physical state of the balancing switches.

0xAAAA = 1010101010101010
0x5555 = 0101010101010101

This alternating pattern indicates that the MC33774A is performing automatic odd/even balancing, which is a normal part of its operation. The status register shows which switches are currently closed (balancing active) or open (inactive) and does not directly reflect the configuration value written to the monitoring enable register.

BRs, Tomas

Re: Unexpected BAL_SWITCH_STAT Register Values on MC33774A

MarkFan — Mon, 01 Sep 2025 08:36:02 GMT

Hi Tomas,

Thasnk for your reply, Actually, only 5 cell connect to MC33774A in our design, according to Missing cell case, I have to coofig BAL_SWITCH_MON_CFG0 and BAL_SWITCH_MON_CFG1 to 0x1f.

So the balancing switches should be

10101 = 0x15 not 0x5555

0101 = 0xa not 0xaaaa

am I misinterpreting how the monitor configuration maps to the STAT registers?

Thank you for your support.

Mark

Re: Unexpected BAL_SWITCH_STAT Register Values on MC33774A

TomasVaverka — Mon, 01 Sep 2025 10:53:56 GMT

Hello Mark,

Your configuration is correct for a 5-cell setup. The status register shows what the switches are doing in real time, not just the ones you are monitoring. Seeing 0xAAAA or 0x5555 is normal during active balancing.

BRs, Tomas