diff options
| author | Vincent Palatin <vpalatin@chromium.org> | 2014-06-18 18:08:04 -0700 |
|---|---|---|
| committer | chrome-internal-fetch <chrome-internal-fetch@google.com> | 2014-07-28 17:12:35 +0000 |
| commit | 47e74b8ca8649d13cbe27db6ae0cee4c50215fee (patch) | |
| tree | 5318a4039a9cfaf6f31d627eeeff1a817c023906 /board | |
| parent | 1faa6ee20273cba9e898e192fc71d0d8ea704b3b (diff) | |
| download | chrome-ec-47e74b8ca8649d13cbe27db6ae0cee4c50215fee.tar.gz | |
zinger: do not trigger OCP on transients
Ensure that the slow OCP (thermal/power protection) is not triggering
for power spikes below 20us, by sampling 4 times (with a 5us sampling
period).
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
BRANCH=none
BUG=chrome-os-partner:28331
TEST=connect Zinger to Firefly+electronic load, test with various
current pulse widths and amplitudes.
Change-Id: Ic8150dbbf191c002bba9e8d3f70beb47af4577b9
Reviewed-on: https://chromium-review.googlesource.com/204588
Reviewed-by: Alec Berg <alecaberg@chromium.org>
Tested-by: Alec Berg <alecaberg@chromium.org>
Commit-Queue: Alec Berg <alecaberg@chromium.org>
Diffstat (limited to 'board')
| -rw-r--r-- | board/zinger/usb_pd_policy.c | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/board/zinger/usb_pd_policy.c b/board/zinger/usb_pd_policy.c index 5123b7c5a0..fded37ab11 100644 --- a/board/zinger/usb_pd_policy.c +++ b/board/zinger/usb_pd_policy.c @@ -205,18 +205,35 @@ int pd_board_checks(void) /* re-enable fast OCP */ adc_enable_watchdog(ADC_CH_A_SENSE, MAX_CURRENT_FAST, 0); - if ((fault == FAULT_FAST_OCP) || (vbus_amp > MAX_CURRENT)) { - debug_printf("OverCurrent : %d mA\n", - vbus_amp * VDDA_MV / CURR_GAIN * 1000 / R_SENSE / ADC_SCALE); + if (fault == FAULT_FAST_OCP) { + debug_printf("Fast OverCurrent\n"); fault = FAULT_OCP; /* reset over-current after 1 second */ fault_deadline.val = get_time().val + OCP_TIMEOUT; return EC_ERROR_INVAL; } + if (vbus_amp > MAX_CURRENT) { + /* 3 more samples to check whether this is just a transient */ + int count; + for (count = 0; count < 3; count++) + if (adc_read_channel(ADC_CH_A_SENSE) < MAX_CURRENT) + break; + /* trigger the slow OCP iff all 4 samples are above the max */ + if (count == 3) { + debug_printf("OverCurrent : %d mA\n", + vbus_amp * VDDA_MV / CURR_GAIN * 1000 + / R_SENSE / ADC_SCALE); + fault = FAULT_OCP; + /* reset over-current after 1 second */ + fault_deadline.val = get_time().val + OCP_TIMEOUT; + return EC_ERROR_INVAL; + } + } if ((output_is_enabled() && (vbus_volt > voltages[volt_idx].ovp)) || (fault && (vbus_volt > voltages[volt_idx].ovp_rec))) { - debug_printf("OverVoltage : %d mV\n", - vbus_volt * VDDA_MV * VOLT_DIV / ADC_SCALE); + if (!fault) + debug_printf("OverVoltage : %d mV\n", + vbus_volt * VDDA_MV * VOLT_DIV / ADC_SCALE); /* TODO(crosbug.com/p/28331) discharge */ fault = FAULT_OVP; /* no timeout */ |