R3710 datasheet(14/18 Pages) ONSEMI

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RHYTHM R3710

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audio output being enabled. This gives the user time to

properly insert the hearing aid before the audio starts,

avoiding the temporary feedback that can occur while the

device is being inserted. During the delay period,

momentary button presses are ignored.

NOTE:

The values set in IDS are relative values from 0

to 11 seconds; not absolute. The POR delay is

relative to the configuration loaded on the

WOLVERINE platform.

Power Management Functionality

As the voltage on the hearing aid battery decreases, an

audible warning is given to the user indicating the battery

life is low. In addition to this audible warning, the hearing

aid takes other steps to ensure proper operation given the

weak supply. The exact hearing aid behaviour in low supply

conditions depends on the selected POR mode. The hearing

aid has three POR modes:

• Shallow Reset Mode

• Deep Reset Mode

• Advanced Mode

Shallow Reset Mode

In Shallow Reset mode, the hearing aid will operate

normally when the battery is above 0.95 V. Once the supply

voltage drops below 0.95 V the audio will be muted and

remain in that state until the supply voltage rises above

1.1 V. Once the supply voltage drops below the control logic

ramp down voltage, the device will undergo a hardware

reset. At this point, the device will remain off until the supply

voltage returns to 1.1 V. When the supply voltage is below

the control logic voltage, but above 0.6 V and rises above the

1.1 V turn on threshold, the device will activate its output

and operate from the memory that was active prior to reset.

If the supply voltage drops below 0.6 V, and rises above the

1.1 V turn on threshold, the device will reinitialize, activate

its output and operate from memory A.

Deep Reset Mode

In Deep Reset mode, the hearing aid will operate normally

when the battery is above 0.95 V. Once the supply voltage

drops below 0.95 V the audio will be muted. The device

remains in this state until the supply voltage drops below the

hardware reset voltage of 0.6 V. When this occurs, the

device will load memory A and operate normally after the

supply voltage goes above 1.1 V.

Advanced Reset Mode

Advanced Reset Mode on R3710 is a more sophisticated

power management scheme than shallow and deep reset

modes. This mode attempts to maximize the device’s usable

battery life by reducing the gain to stabilize the supply based

on the instantaneous and average supply voltage levels.

Instantaneous supply fluctuations below 0.95 V can trigger

up to two 3 dB, instantaneous gain reductions. Average

supply drops below 0.95 V can trigger up to eighteen, 1 dB

average gain reductions.

While the average supply voltage is above 0.95 V, an

instantaneous supply voltage fluctuation below 0.95 V will

trigger an immediate 3 dB gain reduction. After the 3 dB

gain reduction has been applied, the advanced reset model

holds off checking the instantaneous voltage level for a

monitoring period of 30 second in order to allow the voltage

level to stabilize. If after the stabilization time the

instantaneous voltage drops a second time below 0.95 V

during the next monitoring period, the gain will be reduced

an additional 3 dB for a 6 dB total reduction and a 30 second

stabilization time is activated. The advanced reset mode

continues to monitor the instantaneous voltage levels over

30 second monitoring periods. If the instantaneous voltage

remains above 1.1 V during that monitoring period, the gain

will be restored to the original setting regardless of whether

one or two gain reductions are applied. If two gain

reductions are applied and the instantaneous voltage level

remains above 1.0 V for a monitoring period, the gain will

be restored to a 3 dB reduction.

Should the average supply voltage drop below 0.95 V, the

device will then reduce the gain by 1 dB every 10 seconds

until either the average supply voltage rises above 0.95 V or

a total of 18 average gain reductions have been applied, at

which point the audio path will be muted. If the average

supply voltage returns to a level above 1.1 V, the audio path

will first be un−muted, if required. The gain will then be

increased by 1 dB every 10 seconds until either the average

supply voltage drops below 1.1 V, or all average gain

reductions have been removed. No action is taken while the

average supply voltage resides between 0.95 V and 1.1 V.

NOTE:

Instantaneous and average gain reductions are

adjusted independently.

When the instantaneous voltage falls below the hardware

shutdown voltage, the device will undergo a hardware reset.

When it turns back on because the voltage has risen above

the turn−on threshold, it will behave the same as it would in

shallow reset mode.

Low Battery Notification

Notification of the low battery condition via an acoustic

indicator is optionally performed when the battery voltage

drops below a configurable low battery notification

threshold. The low battery indicator is repeated every five

minutes until the device shuts down.

Software and Security

R3710 incorporates the following security features to

protect the device from cloning and against software piracy:

• DLL protection by password − prevents a third party

from using IDS to reconfigure parts.

• Hybrid authentication by 128−bit fingerprint to identify

parts in application software − prevents a third party

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