diff options
| -rw-r--r-- | board/pyro/battery.c | 26 | ||||
| -rw-r--r-- | board/snappy/battery.c | 26 |
2 files changed, 50 insertions, 2 deletions
diff --git a/board/pyro/battery.c b/board/pyro/battery.c index 1b816cadd1..a87c514f51 100644 --- a/board/pyro/battery.c +++ b/board/pyro/battery.c @@ -231,8 +231,32 @@ int charger_profile_override(struct charge_state_data *curr) /* Current and previous battery voltage */ int batt_voltage; static int prev_batt_voltage; + int disch_on_ac; - charger_discharge_on_ac(!(curr->batt.flags & BATT_FLAG_WANT_CHARGE)); + /* + * In light load (<450mA being withdrawn from VSYS) the DCDC of the + * charger operates intermittently i.e. DCDC switches continuously + * and then stops to regulate the output voltage and current, and + * sometimes to prevent reverse current from flowing to the input. + * This causes a slight voltage ripple on VSYS that falls in the + * audible noise frequency (single digit kHz range). This small + * ripple generates audible noise in the output ceramic capacitors + * (caps on VSYS and any input of DCDC under VSYS). + * + * To overcome this issue enable the battery learning operation + * and suspend USB charging and DC/DC converter. + */ + disch_on_ac = curr->batt.is_present == BP_YES && + !battery_is_cut_off() && + !(curr->batt.flags & BATT_FLAG_WANT_CHARGE) && + curr->batt.status & STATUS_FULLY_CHARGED; + + charger_discharge_on_ac(disch_on_ac); + + if (disch_on_ac) { + curr->state = ST_DISCHARGE; + return 0; + } /* * Determine temperature range. The five ranges are: diff --git a/board/snappy/battery.c b/board/snappy/battery.c index 4abdff5534..5ba4c0ac28 100644 --- a/board/snappy/battery.c +++ b/board/snappy/battery.c @@ -159,8 +159,32 @@ int charger_profile_override(struct charge_state_data *curr) /* Current and previous battery voltage */ int batt_voltage; static int prev_batt_voltage; + int disch_on_ac; - charger_discharge_on_ac(!(curr->batt.flags & BATT_FLAG_WANT_CHARGE)); + /* + * In light load (<450mA being withdrawn from VSYS) the DCDC of the + * charger operates intermittently i.e. DCDC switches continuously + * and then stops to regulate the output voltage and current, and + * sometimes to prevent reverse current from flowing to the input. + * This causes a slight voltage ripple on VSYS that falls in the + * audible noise frequency (single digit kHz range). This small + * ripple generates audible noise in the output ceramic capacitors + * (caps on VSYS and any input of DCDC under VSYS). + * + * To overcome this issue enable the battery learning operation + * and suspend USB charging and DC/DC converter. + */ + disch_on_ac = curr->batt.is_present == BP_YES && + !battery_is_cut_off() && + !(curr->batt.flags & BATT_FLAG_WANT_CHARGE) && + curr->batt.status & STATUS_FULLY_CHARGED; + + charger_discharge_on_ac(disch_on_ac); + + if (disch_on_ac) { + curr->state = ST_DISCHARGE; + return 0; + } /* * Determine temperature range. The five ranges are: |