HPM10

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10

HPM10 Working Modes

HPM10 has three working modes represented in the state machine below.

Hearing

Aid

(HA )

Cradle

Mode

(CM)

DS _EN =1

SAFE _MODE =0

Deep

Sleep

(DS)

SAFE

& CH_CONN =0

& SWIN =1

CH_CONN= 1

CH_CONN =0

CH _CONN=1

SAFE_MODE=1 &

CH_CONN=0 &

NO_BUTTON=1

Figure 3. HPM10 State Machine

Deep Sleep Mode: A low power mode with all blocks

turned off. HPM10 can enter Deep Sleep Mode in one of

three ways:

DS_EN pin high. An example use−case for this

transition is when a program is running on the host

DSP, that determines that the hearing aid is not being

worn or the measured battery voltage is below a

specified value and puts the system into Deep Sleep

Mode to save power.

drops below the EOL set point (VEOL level), for the

battery chemistry actively being used to avoid

irreversible battery damage. This is when VBAT<1.0 V

(for AgZN) or 2.2 V<VBAT<3.0 V (for Lithium−Ion).

This will draw the SAFE_MODE status bit to 0.

removed, in case the OTP bit “no_button” is not set.

Cradle Mode: The hearing aid will enter in Cradle Mode

when the hearing Aid is physically connected to Cradle

(CH_CONN=1). In this mode, the hearing aid battery is

being charged.

Once in this state, the following sequence of processes

will occur:

internal latches.

Redundancy Check (CRC) is made by the controller. If

it fails, the system transitions to completion phase in

Cradle Mode and an error flag is set.

process.

The charging process is controlled by a controller and

firmware in ROM.

Hearing Aid Mode: The hearing aid DSP power is supplied

by HPM10 and there is no digital logic running on HPM10.

In this mode, the hearing aid is in normal operation mode and

receives its supply voltage from HPM10. HPM10 can enter

Hearing Aid Mode in two ways:

press. The battery voltage must be in a valid range.

OTP bit NO_BUTTON=1. The battery voltage must be

in a valid range.HPM10 is either clocked with the

Hearing Aid Mode Oscillator, or with the divided

EXT_CLK.

The recommended tasks for the host DSP in Hearing Aid

Mode are as follows:

driving the 3 CLKDIV pins (*)