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Automatic power-down

JP150PCB 1.3PCB 1.4since 26.8.0Jan PřibyslavskýThis page does not apply to the product or PCB revision chosen in the header.

The module can watch its selected input for silence and drop to a lower power level after a configurable period, returning to normal when audio comes back. The feature is disabled by default.

Settings

Setting Range Default
Enable on, off off
Target level any level except NORMAL PWRSTAGE_OFF
Delay 10 to 65535 s (about 18 h) 1800 s (30 min)
Silence threshold raw level-meter units 5

Silence is measured at the source, ahead of the volume control. A muted power stage that is still fed audio does not power down; paused audio counts as silence, so a paused source eventually powers the module down. The default threshold treats only near-digital silence as silent; a source with a residual DC offset or dither may never let the module power down, in which case raise the threshold.

Device > Power Modes, section Automatic power-down: the Automatic power mode switch enables or disables the feature and applies at once. Power down to chooses the target level, After silence of the delay in minutes and seconds, and Silence threshold the level below which the input counts as silent (0 would never be silent); Apply power-mode settings sends the three values to the module. While the timer runs, the page shows the countdown.

Device, Power Modes
Device > Power Modes: the power level, the automatic power-down and, on PCB 1.4, the 12 V trigger.

Over the control interface

Setting Commands
Enable SYS:POWER:AUTO?, SYS:POWER:AUTO with 0 or 1
Target level SYS:POWER:AUTO:MODE?, SYS:POWER:AUTO:MODE with the level
Delay SYS:POWER:AUTO:DELAY?, SYS:POWER:AUTO:DELAY with the seconds
Silence threshold SYS:POWER:AUTO:THRESHOLD?, SYS:POWER:AUTO:THRESHOLD with the raw value

SYS:POWER:AUTO:STATE? returns the enable state, whether the timer runs, the configured and the effective target, the delay and the elapsed and remaining seconds, so a host can show a countdown. The syntax and the answers are in the SYS:POWER reference.

Wake sources

The module returns to normal operation on an encoder turn or press, on audio returning on the selected input, on a SigmaStudio programmer appearing on the DSP bus, and on any reset. The encoder action that wakes the module only wakes it: it does not also change the volume or the input, which you cannot see while powered down. On PCB 1.4 the 12 V trigger can wake the module as well.

Target level clamping by input

The module limits itself to a level it can reliably wake from, which depends on the selected input.

Selected input Deepest level entered Reason
USB STANDBY Incoming USB audio is detected by the host MCU directly.
Bluetooth STANDBY The Bluetooth module reports the playback state.
Wi-Fi SLEEP STANDBY would remove power from the Wi-Fi module.
S/PDIF, I2S PWRSTAGE_OFF Only the DSP sees these signals, so it must keep running.
Sine generator never powers down The internal generator is never silent.

A configured target deeper than the clamp is silently reduced; both the configured and the effective target are readable. USB caveat: powered down, the module sees USB packets arriving but not their content, so a computer that streams digital silence rather than stopping its stream reads as active and wakes the module about once per delay. Select another input, or leave automatic power-down off, with such a host.

Automatic power-down is suspended while a SigmaStudio programmer is active, and, with the trigger priority set, while the 12 V trigger holds the module awake.