BQ25798: VAC1/VAC2

Yoshinobu Kagawa

Expert 2030 points

Part Number: BQ25798
Other Parts Discussed in Thread: BQ25790

I sent you the actual register setting procedure for switching the supply source from VAC2 to VAC1. (Attached document)
I have already confirmed that it is possible to switch the supply source to VAC1 using this procedure, but is there a possibility that after the switch, the IINDPM register will be overwritten with the value of ILIM_HIZ instead of the already set 1600mA without any operation from the host?

【bq25798】Register setting procedure for switching supply source from VAC2 to VAC1.xlsx

Regards,
Kagawa

over 1 year ago

0 Christian Moyer over 1 year ago

TI__Mastermind 31551 points

Hello Yoshinobu,

I have to review this information, but I will provide an update after I gather more information.

Best Regards,

Christian.

0 Christian Moyer over 1 year ago in reply to Christian Moyer

TI__Mastermind 31551 points

Hello Yoshinobu,

I see that you said the D+D- detection is not being used, but If you disable AUTO_INDET_EN, REG11[6]=0, Do you still see this behavior when you switch input sources?

Best Regards,

Christian.

0 Yoshinobu Kagawa over 1 year ago in reply to Christian Moyer

Expert 2030 points

Hello Christian-san,

When AUTO_INDET_EN = 1, the IINDPM value based on the resistance value of ILIM_HIZ is compared with the input current limit value (Unknown Adapter - 3A, etc.) obtained by the BC1.2 judgment, and the lower value is set in the IINDPM register. I understood that the IINDPM value is set based on the ILIM_HIZ value because the D+D- pin is open at this point and the ILIM_HIZ value is lower than the BC1.2 value (Unknown Adapter - 3A). However, if you wait a few seconds after that (within 4 seconds if you refer to the last line on "bq25798_AUTO_INDET_EN0.log"), you can overwrite the IINDPM register with a value lower than ILIM_HIZ. In other words, if AUTO_INDET_EN=1 is set, is there a period of time when the IINDPM register is not updated even if an overwrite operation from the host SoC is performed within a short period of time? If so, I would like to know how many seconds of waiting time is required after the supply source is switched from VAC2 to VAC1, after the BC1.2 decision is made inside the chip and compared to ILIM_HIZ, before the chip can be overwritten with a smaller value.

Fullscreen bq25798_AUTO_INDET_EN0.log Download

Fri Apr 05 09:32:09 JST 2024

Device Name = bq25798
Firmware Version = 2.00


Sample,DateTime,ElapsedTime,REG00,REG01,REG03,REG05,REG06,REG08,REG09,REG0A,REG0B,REG0D,REG0E,REG0F,REG10,REG11,REG12,REG13,REG14,REG15,REG16,REG17,REG18,REG19,REG1B,REG1C,REG1D,REG1E,REG1F,REG20,REG21,REG22,REG23,REG24,REG25,REG26,REG27,REG28,REG29,REG2A,REG2B,REG2C,REG2D,REG2E,REG2F,REG30,REG31,REG33,REG35,REG37,REG37,REG3B,REG3D,REG3F,REG41,REG43,REG45,REG47,REG48,LogRowTime(ms),LogStatus
1,2024-04-05 09:32:13,4.001,10,02D0,0064,2E,0032,C3,23,63,00DC,4B,3B,B2,95,01,00,A1,B6,AA,C0,06,54,0032,8D,6A,81,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,01E4,0115,1441,0000,1446,1A94,1AC9,0256,0031,0000,0000,00,19,896,SUCCESS
2,2024-04-05 09:32:17,8.002,10,02D0,0064,2E,0032,C3,23,63,00DC,4B,3B,B2,95,01,00,A1,B6,AA,C0,06,54,0032,8D,6A,81,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,01E4,0115,1441,0000,1445,1A95,1AC9,0256,0031,0000,0000,00,19,895,SUCCESS
3,2024-04-05 09:32:21,12.002,10,02D0,0064,2E,0032,C3,23,63,00DC,4B,3B,B2,95,01,00,A1,B6,AA,C0,06,54,0032,8D,6A,81,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,01E4,0115,1443,0000,1444,1A97,1AC9,0256,0031,0000,0000,00,19,894,SUCCESS
4,2024-04-05 09:32:25,16.003,10,02D0,0064,2E,0032,C3,23,63,00DC,4B,3B,B2,95,01,00,A1,B6,AA,C0,06,54,0032,8D,6A,81,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,01E4,0115,1443,0000,1444,1A98,1ACC,0257,0031,0000,0000,00,19,893,SUCCESS
5,2024-04-05 09:32:29,20.003,10,02D0,0064,6D,00A0,C3,23,63,00DC,4B,3B,B2,95,01,00,61,B6,AA,C0,06,54,0047,0F,6A,41,C0,00,00,00,8B,C0,00,00,01,00,FD,D7,7F,1F,FF,F4,80,00,00,02AC,0440,2F96,2F95,1497,1B65,1BBF,0257,003B,0000,0000,00,19,893,SUCCESS
6,2024-04-05 09:32:33,24.004,10,02D0,0064,6D,00A0,C3,23,63,00DC,4B,3B,B2,95,01,00,61,B6,AA,C0,06,54,0047,0F,6A,41,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,02AD,0440,2F95,2F95,1497,1B6E,1BC9,0257,003C,0000,0000,00,19,893,SUCCESS
7,2024-04-05 09:32:37,28.004,10,02D0,0064,6D,00A0,C3,23,63,00DC,4B,3B,B2,95,01,00,61,B6,AA,C0,06,54,0047,0F,6A,41,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,02AD,0440,2F94,2F95,1497,1B74,1BCF,0257,003C,0000,0000,00,19,893,SUCCESS
8,2024-04-05 09:32:41,32.004,10,02D0,0064,6D,00A0,C3,23,63,00DC,4B,3B,B2,95,01,00,61,B6,AA,C0,06,54,0047,0F,6A,41,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,02AE,0440,2F93,2F96,1497,1B7A,1BD6,0257,003C,0000,0000,00,19,892,SUCCESS
9,2024-04-05 09:32:45,36.004,10,02D0,0064,2D,0032,C3,23,63,00DC,4B,3B,B2,95,01,00,A1,B6,AA,C0,06,54,0032,8D,6A,81,C0,00,00,00,DB,D0,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,01D2,010C,1445,0000,1446,1AB0,1AEA,0255,0033,0000,0000,00,19,893,SUCCESS

Fullscreen bq25798_AUTO_INDET_EN1.log Download

Fri Apr 05 09:11:06 JST 2024

Device Name = bq25798
Firmware Version = 2.00


Sample,DateTime,ElapsedTime,REG00,REG01,REG03,REG05,REG06,REG08,REG09,REG0A,REG0B,REG0D,REG0E,REG0F,REG10,REG11,REG12,REG13,REG14,REG15,REG16,REG17,REG18,REG19,REG1B,REG1C,REG1D,REG1E,REG1F,REG20,REG21,REG22,REG23,REG24,REG25,REG26,REG27,REG28,REG29,REG2A,REG2B,REG2C,REG2D,REG2E,REG2F,REG30,REG31,REG33,REG35,REG37,REG37,REG3B,REG3D,REG3F,REG41,REG43,REG45,REG47,REG48,LogRowTime(ms),LogStatus
1,2024-04-05 09:11:10,4.000,10,02D0,0064,2E,0032,C3,23,63,00DC,4B,3B,B2,95,41,00,A1,B6,AA,C0,06,54,0032,8D,6A,81,C0,00,00,00,DB,D0,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,01E2,0000,1443,0000,1444,1A1F,1A26,0259,0034,0000,0000,00,19,880,SUCCESS
2,2024-04-05 09:11:14,8.000,10,02D0,0064,2E,0032,C3,23,63,00DC,4B,3B,B2,95,41,00,A1,B6,AA,C0,06,54,0032,8D,6A,81,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,01E2,0000,1444,0000,1446,1A1D,1A1E,0259,0034,0000,0000,00,19,881,SUCCESS
3,2024-04-05 09:11:18,12.001,10,02D0,0064,2E,0032,C3,23,63,00DC,4B,3B,B2,95,41,00,A1,B6,AA,C0,06,54,0032,8D,6A,81,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,01E2,0000,1445,0000,1444,1A11,1A13,0259,0034,0000,0000,00,19,896,SUCCESS
4,2024-04-05 09:11:22,16.001,10,02D0,0064,2E,0032,C3,23,63,00DC,4B,3B,B2,95,41,00,A1,B6,AA,C0,06,54,0032,8D,6A,81,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,01E2,0000,1444,0000,1446,1A1A,1A1C,0259,0034,0000,0000,00,19,895,SUCCESS
5,2024-04-05 09:11:26,20.002,10,02D0,0064,2E,0032,C3,23,63,00DC,4B,3B,B2,95,41,00,A1,B6,AA,C0,06,54,0032,8D,6A,81,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,01E2,0000,1444,0000,1447,1A15,1A10,0259,0034,0000,0000,00,19,895,SUCCESS
6,2024-04-05 09:11:30,24.002,10,02D0,0064,6D,00AC,C3,23,63,00DC,4B,3B,B2,95,41,00,61,B6,AA,C0,06,54,0086,0F,6A,41,C0,00,00,00,8B,C0,40,00,01,00,FD,D7,7F,1F,FF,F4,80,00,00,0484,0406,2EFF,2F09,149D,1BB3,1C04,025C,0051,0000,000B,00,19,894,SUCCESS
7,2024-04-05 09:11:34,28.002,10,02D0,0064,6D,00AC,C3,23,63,00DC,4B,3B,B2,95,41,00,61,B6,AA,C0,06,54,0087,0F,6A,41,C0,00,00,00,80,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,04EF,0438,2EF4,2F02,149E,1BBE,1C15,025B,005B,0005,000E,00,19,894,SUCCESS
8,2024-04-05 09:11:38,32.002,10,02D0,0064,6D,00AC,C3,23,63,00DC,4B,3B,B2,95,41,00,61,B6,AA,C0,06,54,0090,0F,6A,41,C0,00,00,00,80,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,04E8,0453,2EF6,2F0D,14A0,1BCB,1C1E,025B,005D,0004,000A,00,19,893,SUCCESS
9,2024-04-05 09:11:42,36.003,10,02D0,0064,6D,00AC,C3,23,63,00DC,4B,3B,B2,95,41,00,61,B6,AA,C0,06,54,0090,0F,6A,41,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,04D6,0458,2EFF,2F06,14A0,1BCC,1C25,025B,005F,0001,000E,00,19,893,SUCCESS
10,2024-04-05 09:11:46,40.003,10,02D0,0064,6D,00AC,C3,23,63,00DC,4B,3B,B2,95,41,00,61,B6,AA,C0,06,54,0090,0F,6A,41,C0,00,00,00,00,00,00,00,00,00,FD,D7,7F,1F,FF,F4,80,00,00,04D5,0451,2EFC,2F07,149F,1BD1,1C29,025B,005F,0000,000A,00,19,894,SUCCESS

Regards,
Kagawa

0 Christian Moyer over 1 year ago in reply to Yoshinobu Kagawa

TI__Mastermind 31551 points

Hello Kagawa,

We do not have the data available to determine the waiting time that is required after the supply source is switched from VAC2 to VAC1, after the BC1.2 decision is made inside the chip and compared to ILIM_HIZ, before the chip can be overwritten with a smaller value.

Best Regards,

Christian.

0 Yoshinobu Kagawa over 1 year ago in reply to Christian Moyer

Expert 2030 points

Hello Christian-san,

In a past question, you answered that the minimum timing required for BC1.2 determination is a wait time of 2 seconds or less.
I think the following QA is probably the one you are referring to, but please allow me to confirm the relevance of what you are responding to to and the waiting time in this case.

BQ25790: VAC_OVP - Power management forum - Power management - TI E2E support forums

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1206859/bq25790-vac_ovp

This time HVDCP detection is disabled. Therefore, am I correct in understanding that after the BC1.2 decision and ILIM_HIZ resistor division are compared, a wait of more than 900 ms is required before the IINDPM register is updated?

Regards,
Kagawa

0 Christian Moyer over 1 year ago in reply to Yoshinobu Kagawa

TI__Mastermind 31551 points

Hello Kagawa,

Yoshinobu Kagawa said:
This time HVDCP detection is disabled. Therefore, am I correct in understanding that after the BC1.2 decision and ILIM_HIZ resistor division are compared, a wait of more than 900 ms is required before the IINDPM register is updated?

As Jeff stated, The datasheet doesn't give the exact timing. USB BC1.2 spec has as minimum required timing (up to 900ms) and then we added the HVDCP detection which doubled the time.

Based on his statement I would assume after disabling HVDCP a wait of more than 900 ms is required before the IINDPM register is updated, but we don't have the data to show how much longer it would take.

Best regards,

Christian.