Power Source; Power On / Off Control - Panasonic EB-G60 Service Manual

The Power Management Block consists of six parts as follows:

1. Power Source

2. Power On/Off Control
3. Power Source Failure detection
4. Voltage Regulation
5. Battery Charging & Monitoring
6. Accessory Control
5.15.2. Power Source
The battery comprises a single Lithium-Ion (Li-Ion) cell with a nominal voltage of 3.7 V and 780 mAh capacities. This type
of battery has an advantage in weight and size over Nickel Metal Hydride (Ni-MH) cells.

5.15.3. Power On / Off Control

The power on sequence can begin when VBAT >2.6 V or VBACKUP >2.6 V. In this state IOTA (U8) is in Power On
Condition and internal supply UPR is active. RESPWRONZ signal to G2 (U1) is released high.
If IOTA is in the Power On Condition, one of following conditions start s the Power Up sequence.
8 Power key is pushed for more than 30 ms.
8 RPWON input goes high to low for more than 30 ms (e.g. accessory is connected or external RTC signal is activated).
8 EXTPWR voltage is higher than (VBAT+0.4) V.
8 G2 RTC ALARM signal goes high.
The Power Up sequence is as follows:
1. Local Oscillator OSCAS is started (if not already active for debouche operation).
2. IOTA internal band gap reference is activated.
3. If VBAT < 3.2 V after a timeout of 51.2 ms OSCAS is stopped and Power Up sequence is aborted.
4. Charge pump is enabled.
5. All regulators are enabled.
6. Power Up status bit and internal Reset bits are set.
7. ONnOFF signal is set to activate G2.
8. ARM in G2 starts running software using 32 kHz clock, and also starts 13 MHz clock.
The following Power Down sequence can only be started by G2 setting the DEVICE_OFF bit in IOTA or, in emergency
case, when VBAT < 2.7 V (or VBAT < Vbackup & VBAT < 2.8 V):
1. If emergency case INT1 is set low by IOTA.
2. IOTA starts an internal 150 µs watchdog timer to allow G2 to shutdown.
3. On_nOff signal is reset to deactivate G2.
4. All regulators are disabled.
5. IOTA internal band gap reference is deactivated.
6. OSCAS is stopped.
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