MC33774 balancing during sleep mode

[Sally_Wang]

你好，工程师：

我在使用MC33774遇到一个问题，我需要做一个关于MC33774的功耗管控，需要实现MC33774在休眠时可以均衡，在官方提供的datasheet 的 第12也 7.1.1.2的sleep mode 中提到了在休眠状态下是可能可以均衡，手册中并没有提到完成的如何配置这个模式，想请问有具体的配置参数参考值吗，我自己做了，但是均衡开了，通道的功耗没有下降，或者进入了休眠状态，但均衡不能打开，需要技术人员能提供这方面的技术支持，谢谢！

SALLY  

2025.5.9

[JozefKozon]

Hello Sally,

for your question please download and refer to the AN14084 "MC33774A cell balancing modes". Please download this document from the MC33774 product page, under the Secure section.

Please note, you need to have a valid NDA with NXP and you need to be registered on the nxp.com to be able to download the confidential documents.

With Best Regards,

Jozef

[Sally_Wang]

Hi,Jozef:

I have downloaded the reference document ANI4084. However, it only states that balancing during sleep is possible but does not explicitly specify the parameter configurations for balancing in sleep mode. The issue I'm encountering is that when I enable balancing for one cell in sleep mode, the chip's power consumption does not decrease.

Best Regards！

Sally

[JozefKozon]

Hi Sally,

please refer to the section 8. in the AN14084. You can set the prebalancing timer to postpone balancing after the MC33774 switches to sleep mode. E.g. set the prebalancing timer to 30s and send the MC33774 to sleep mode. Then the balancing starts in the sleep mode. Please refer to the Figure 9. in the AN14084. 

Please also refer to the sections 7.5.3.5 and 12.1.73 in the MC33774 full datasheet for the prebalance timer settings.

With Best Regards,

Jozef

[Sally_Wang]

Hi,Jozef:

  Thank you for  recommandation. I referred to Part 8 and Figure 9 of document AN14084, debugged and set according to the parameters provided in the manual :BAL_GLOB_CFG= 0x03，BAL_GLOB_TO_TMR= 0x06，BAL_CH_CFG0= 0x1FFF,BAL_CH_CFG1 = 0x00，BAL_PRE_TMR = 0x03， After configuring channel 8, it was found that balancing could not be turned on after running. Is it reasonable to configure parameters such as balancing ?

Sally

[JozefKozon]

Hi Sally,

I think the BAL_GLOB_CFG.BALEN bit should be set to 1 as last. Because the pre-balancing timer starts as soon as the BAL_GLOB_CFG.BALEN=1. Please set the all the registers listed in the Figure 9. from top to bottom, except the BAL_GLOB_CFG.BALEN bit. Make sure that no Cell has lower voltage than the UV0 level set in the PRMM_VC_UV0_TH_CFG (possibly set it to 0x00 default). And as last set the BAL_GLOB_CFG.BALEN bit to 1. BAL_GLOB_CFG= 0x03. 

With Best Regards,

Jozef

[Sally_Wang]

Hi Jozef：
Thank you !Find the cause of the problem. The reason for not being able to open the balance is that there was an error in the steps to enter sleep mode. Refer to section 7.1.1 of the manual. Is the undervoltage and overvoltage information of multiple nodes broadcasted or sent individually by a single node?

Sally 

[JozefKozon]

Hi Sally, 

for your question regarding the overvoltage and undervoltage faults, and results if registered, please refer to the section 7.2.1 in the MC33774A full datasheet. This is very complex question. Depending where the UV/OV fault is registered, the action can be different, UV/OV can force Power On Reset. 

Additional information to the UV/OV faults can be found in the MC33774A safety manual, section 12.7.1.

Please download the MC33774A S.M. from the MC33774 product page, under the Secure section. 

With Best Regards,

Jozef