SLUUCA6 October 2021 BQ27Z746
During BUFFER mode, the cell voltage is buffered and output on the BAT_SP and BAT_SN pins with a configurable offset. However, to produce an offset on BAT_SP, there must be sufficient voltage headroom on the PACK pin above the cell voltage, which is enforced by Buffer Mode PACK Margin. BUFFER mode typically coincides with cell undervoltage protection (CUV) but is separate for added flexibility.
Status | Condition | Action |
---|---|---|
Activate | OperationStatusA()[XCHG] = 0 AND Current() < RLO Charge Threshold AND Voltage() ≤ Buffer Mode Threshold for Buffer Mode Delay AND PACK pin voltage ≥ Voltage() + Buffer Mode PACK Margin | Enter BUFFER mode |
Exit | OperationStatusA()[XCHG] = 1 OR Current() ≥ RLO Charge Threshold OR Voltage() ≥ Buffer Mode Recovery OR PACK pin voltage < Voltage() + Buffer Mode PACK Margin | Exit BUFFER mode |
When transitioning from BUFFER mode to RLO Mode or RLO HARGE Mode, the battery sensing output is configured to Transition Config for Transition Delay to perform a make-before-break switch between the low resistors and buffers.
Class | Subclass | Name | Type | Min | Max | Default | Unit |
---|---|---|---|---|---|---|---|
Settings | Batt Sense | Transition Config | H1 | 0x00 | 0x6C | 0x44 | Hex |
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
RSVD | RLO_P_EN | RLO_N_EN | RSVD | BUF_P_EN | BUF_N_EN | RSVD | RSVD |
RSVD (Bit 7): Reserved. Do not use. | ||
RLO_P_EN (Bit 6): Low resistor (RLO) enable on BAT_SP during transition | ||
1 = | Enable low resistor between BAT and BAT_SP (default) | |
0 = | Disable low resistor between BAT and BAT_SP | |
RLO_N_EN (Bit 5): Low resistor (RLO) enable on BAT_SN during transition | ||
1 = | Enable low resistor between VSS and BAT_SN | |
0 = | Disable low resistor between VSS and BAT_SN (default) | |
RSVD (Bit 4): Reserved. Do not use. | ||
BUF_P_EN (Bit 3): Buffer enable on BAT_SP during transition | ||
1 = | Enable buffer between BAT and BAT_SP | |
0 = | Disable buffer between BAT and BAT_SP (default) | |
BUF_N_EN (Bit 2): Buffer enable on BAT_SN during transition | ||
1 = | Enable buffer between VSS and BAT_SN (default) | |
0 = | Disable buffer between VSS and BAT_SN | |
RSVD (Bits 1–0): Reserved. Do not use. |
Class | Subclass | Name | Type | Min | Max | Default | Unit |
---|---|---|---|---|---|---|---|
Settings | Batt Sense | Buffer Mode Threshold | I2 | 0 | 32767 | 2500 | mV |
Settings | Batt Sense | Buffer Mode Delay | U1 | 0 | 255 | 1 | s |
Settings | Batt Sense | Buffer Mode Recovery | I2 | 0 | 32767 | 2900 | mV |
Settings | Batt Sense | Buffer Mode PACK Margin | I2 | -1000 | 1000 | 100 | mV |
Settings | Batt Sense | Transition Delay | U2 | 0 | 1000 | 250 | 2 µs |