Hello,
we are facing issues in using the MP2650 to as boost charger for a 4S Li-ion battery with 5 V input.
We are using the EV2650-V-01A evaluation board.
Below a dump of the registers and the readings from the MP2650 ADC in the different setups.
If we use a 2S battery everything works as expected:
- with 5 V input and no battery (SETUP 2S-1), we get 8.40 V output
- with 5 V input and a 2S battery (SETUP 2S-2), we get 8.40 V output, the battery is charged and the power path is correctly handled (charge_current = input_current - sys_current)
- with no input and a 2S battery (SETUP 2S-3), the system is powered from battery
If we use a 4S battery, we can’t power the system or charge the battery in any way.
All registers are at their default values, except for register 0x07 where BAT_NUM is set to 11 (4 cells configuration), and register 0x0B where PROCHOT/PSYS_CFG is set to 11 (enable PSYS).
The current situation is:
- with 5 V input and no battery (SETUP 4S-1), we get 0.95 V output and we hear the DC-DC not starting (clicking noise). The status register REG13h reports BATT_UVLO + VSYS_UV + ACOK, the fault register REG14h reports nothing.
- with 5 V input and a 4S battery (SETUP 4S-2), we get 13.60 V output but the power supply turns off due to OVERVOLTAGE PROTECTION, indeed we measure 7-8 V at the input with the power supply already disconnected. The status register REG13h and the fault register REG14h reports nothing.
- with no input and a 4S battery (SETUP 4S-3), the system is powered from battery, but the ADC reports 0 V for both VBATT and VSYS. The status register REG13h and the fault register REG14h reports nothing.
- time to time we can connect the 4S battery without the power supply triggering the OVER VOLTAGE PROTECTION (CASE 4S-4), but the charge does not start. The ADC reports only VIN, while all other values are zero. From our instruments we see that the system is powered from the battery, not from the power supply. The status register REG13h reports BATT_UVLO and the fault register REG14h reports nothing.
Are we missing some needed configuration to work with a 4S battery? Do you have any advice?
Thanks,
Martino
########################################
2 cell battery configuration
All default setting except:
0x0B: 00000011 (enable PROCHOT and PSYS)
########################################
--------------------
SETUP 2S-1
VIN: 5 V
Battery: disconnected
LOAD: 24 Ohm
--------------------
REGISTERS
0x00: 00011110
0x01: 00101101
0x02: 00010100
0x03: 00110010
0x04: 01001110
0x05: 00000011
0x06: 00000101
0x07: 00010100
0x08: 00010110
0x09: 01001100
0x0A: 00110110
0x0B: 00000011
0x0C: 11000000
0x0D: 00000001
0x0E: 00100011
0x0F: 00011110
0x10: 00000001
0x11: 11111111
0x12: 01110111
0x13: 00001011
0x14: 00000000
ADC
VIN: 4.80 V
IIN: 675.00 mA
VSYS: 8.35 V
PSYS: 3.00 W
VBATT: 8.40 V
ICHARGE: 0.00 mA
IDIS: 0.00 mA
--------------------
SETUP 2S-2
VIN: 5 V
Battery: 2S
LOAD: 24 Ohm
--------------------
REGISTERS
0x00: 00011110
0x01: 00101101
0x02: 00010100
0x03: 00110010
0x04: 01001110
0x05: 00000011
0x06: 00000101
0x07: 00010100
0x08: 00010110
0x09: 01001100
0x0A: 00110110
0x0B: 00000011
0x0C: 11000000
0x0D: 00000001
0x0E: 00100011
0x0F: 00011110
0x10: 00000001
0x11: 11111111
0x12: 01110111
0x13: 00111011
0x14: 00000000
ADC
VIN: 4.80 V
IIN: 1450.00 mA
VSYS: 7.10 V
PSYS: 3.50 W
VBATT: 7.10 V
ICHARGE: 500.00 mA
IDIS: 0.00 mA
--------------------
SETUP 2S-3
VIN: disconnected
Battery: 2S
LOAD: 24 Ohm
--------------------
REGISTERS
0x00: 00011110
0x01: 00101101
0x02: 00010100
0x03: 00110010
0x04: 01001110
0x05: 00000011
0x06: 00000101
0x07: 00010100
0x08: 00010110
0x09: 01001100
0x0A: 00110110
0x0B: 00000011
0x0C: 11000000
0x0D: 00000001
0x0E: 00100011
0x0F: 00011110
0x10: 00000001
0x11: 11111111
0x12: 01110111
0x13: 00000000
0x14: 00000000
ADC
VIN: 0.00 V
IIN: 0.00 mA
VSYS: 6.95 V
PSYS: 0.00 W
VBATT: 7.00 V
ICHARGE: 0.00 mA
IDIS: 0.00 mA
########################################
4 cell battery configuration
All default setting except:
0x07: 11010100 (default config + 4 cell)
0x0B: 00000011 (enable PROCHOT and PSYS)
########################################
--------------------
SETUP 4S-1
VIN: 5 V
Battery: disconnected
LOAD: 24 Ohm
--------------------
REGISTERS
0x00: 00011110
0x01: 00101101
0x02: 00010100
0x03: 00110010
0x04: 01001110
0x05: 00000011
0x06: 00000101
0x07: 11010100
0x08: 00010110
0x09: 01001100
0x0A: 00110110
0x0B: 00000011
0x0C: 11000000
0x0D: 00000001
0x0E: 00100011
0x0F: 00011110
0x10: 00000001
0x11: 11111111
0x12: 01110111
0x13: 11000010 (BATT_UVLO + VSYS_UV + ACOK)
0x14: 00000000
ADC
VIN: 4.90 V
IIN: 25.00 mA (MEASURED: 120 mA)
VSYS: 0.00 V (MEASURED: 0.95)
PSYS: 2.00 W
VBATT: 0.00 V
ICHARGE: 0.00 mA
IDIS: 0.00 mA
--------------------
SETUP 4S-2
VIN: 5 V (OVERVOLTAGE PROTECTION)
Battery: 4S
LOAD: 24 Ohm
--------------------
REGISTERS
0x00: 00011110
0x01: 00101101
0x02: 00010100
0x03: 00110010
0x04: 01001110
0x05: 00000011
0x06: 00000101
0x07: 11010100
0x08: 00010110
0x09: 01001100
0x0A: 00110110
0x0B: 00000011
0x0C: 11000000
0x0D: 00000001
0x0E: 00100011
0x0F: 00011110
0x10: 00000001
0x11: 11111111
0x12: 01110111
0x13: 00000000
0x14: 00000000
ADC
VIN: 0.00 V
IIN: 0.00 mA
VSYS: 0.00 V (MEASURED: 13.60)
PSYS: 0.00 W
VBATT: 0.00 V (MEASURED: 13.60)
ICHARGE: 0.00 mA
IDIS: 0.00 mA
--------------------
SETUP 4S-3
VIN: disconnected
Battery: 4S
LOAD: 24 Ohm
--------------------
REGISTERS
0x00: 00011110
0x01: 00101101
0x02: 00010100
0x03: 00110010
0x04: 01001110
0x05: 00000011
0x06: 00000101
0x07: 11010100
0x08: 00010110
0x09: 01001100
0x0A: 00110110
0x0B: 00000011
0x0C: 11000000
0x0D: 00000001
0x0E: 00100011
0x0F: 00011110
0x10: 00000001
0x11: 11111111
0x12: 01110111
0x13: 00000000
0x14: 00000000
ADC
VIN: 0.00 V
IIN: 0.00 mA
VSYS: 0.00 V (MEASURED: 13.60)
PSYS: 0.00 W
VBATT: 0.00 V (MEASURED: 13.60)
ICHARGE: 0.00 mA
IDIS: 0.00 mA
--------------------
SETUP 4S-4
VIN: 5 V (without OVP)
Battery: 4S
LOAD: 24 Ohm
--------------------
REGISTERS
0x00: 00011110
0x01: 00101101
0x02: 00010100
0x03: 00110010
0x04: 01001110
0x05: 00000011
0x06: 00000101
0x07: 11010100
0x08: 00010110
0x09: 01001100
0x0A: 00110110
0x0B: 00000011
0x0C: 11000000
0x0D: 00000001
0x0E: 00100011
0x0F: 00011110
0x10: 00000001
0x11: 11111111
0x12: 01110111
0x13: 10000010
0x14: 00000000
ADC
VIN: 4.90 V
IIN: 50.00 mA
VSYS: 0.00 V
PSYS: 0.00 W
VBATT: 0.00 V
ICHARGE: 0.00 mA
IDIS: 400.00 mA