SONGUO Default FET circuit add to pch FET

** SONGUO Default FET circuit add to p-ch FET Tuning#1

** SONGUO Default FET circuit add to p-ch FET & TR ※ Added 6 page circuit of TIDA-01093. “ 20 -Series Battery Management Module Reference Design (Rev. A) “ Tuning#2

** SONGUO Default FET circuit add to p-ch FET/Zener/Resistor ※ Added 7 page circuit of slua 773. pdf(TI). “bq 77905 Using Multiple FETs“ Tuning#3

Reviewing the details provided so far, I have few comments regarding the current implementation of the CHG and DCHG methods. 1. Please update C 57 to >=1 u. F. 2. I noticed from the diagrams that the gate voltage seems to plateau around 4 V, what is the duration of that transition? Can you please share actual waveforms captures? 3. I can’t tell from the diagrams but I believe what you’re experiencing is a slow falling edge of the CHG which is likely caused by the gate to source resistor R 301. This is likely the source of the FETs heating and could possibly lead to failures. 4. To overcome this, it is important to add few components to enhance turn-off speed: a. You could implement a local turn-off circuit near the gates using discrete PNP transistor as shown on Figure 13 or SLUA 618 A. b. Components similar to Figure 6 in SLUA 773 should also resolve the CHG turn-off delay issue with the obvious trade-off of additional components. 5. In either case, A P-ch FET or PNP BJT is highly recommended from output stage CHG channel. This low-cost transistor is a must for reliability and robustness as discuss in BQ datasheet as Source of CHG FETs are not referenced to GND but rather PACK- where significant negative transients can expose OUTB and subject it to failure.

1. Please update C 57 to >=1 u. F SONGUO : I changed the C 57(100 n. F 1 u. F), but same problem. 1 u. F Tuning#4

2. I noticed from the diagrams that the gate voltage seems to plateau around 4 V, what is the duration of that transition? Can you please share actual waveforms captures? SONGUO : Charging On/Off(3 s) R 301(1 M 150 k) Next Page ↓ Tuning#5

SONGUO : Add to p-ch FET and Charging On/Off(3 s) Tuning#6 R 301(1 M 150 k) Next Page ↓

SONGUO : Add to p-ch FET & Q 35/Q 36/R 154/R 91 and Charging On/Off(3 s), but same problem. R 301(1 M 150 k) ※ Added 6 page circuit of TIDA-01093. “ 20 -Series Battery Management Module Reference Design (Rev. A) “ Tuning#7