NXP Semiconductors
PF4210
14-channel power management integrated circuit (PMIC) for audio/video applications
10.4.6.7 Coin cell battery backup
The LICELL pin provides for a connection of a coin cell backup battery or a super
capacitor. If the voltage at VIN goes below the VIN threshold (VTL1 and VTL0), contact-
bounced, or removed, the coin cell maintained logic is powered by the voltage applied to
LICELL.
The supply for internal logic and the VSNVS rail switches over to the LICELL pin when
VIN goes below VTL1 or VTL0, even in the absence of a voltage at the LICELL pin,
resulting in clearing of memory and turning off of VSNVS. When system operation
below VTL1 is required, for systems not utilizing a coin cell, connect the LICELL pin to
any system voltage between 1.8 V and 3.0 V. A small capacitor should be placed from
LICELL to ground under all circumstances.
10.4.6.7.1 Coin cell charger control
The coin cell charger circuit functions as a current-limited voltage source, resulting in the
CC/CV taper characteristic typically used for rechargeable Lithium-Ion batteries. The coin
cell charger is enabled via the COINCHEN bit while the coin cell voltage is programmable
through the VCOIN[2:0] bits on register COINCTL in Table 111. The coin cell charger
voltage is programmable. In the on state, the charger current is fixed at ICOINHI. In sleep
and standby modes, the charger current is reduced to a typical 10 µA. In the off state,
coin cell charging is not available as the main battery could be depleted unnecessarily.
The coin cell charging stops when VIN is below UVDET.
Table 110.ꢀCoin cell charger voltage
VCOIN[2:0]
000
VCOIN (V) [1]
2.50
001
2.70
010
2.80
011
2.90
100
3.00
101
3.10
110
3.20
111
3.30
[1] Coin cell voltage selected is based on the type of LICELL used in the system.
Table 111.ꢀRegister COINCTL - ADDR 0x1A
Name
Bit number
R/W
Default Description
VCOIN
2:0
R/W
0x00
Coin cell charger output voltage selection. See Table 110 for
all options selectable through these bits.
Enable or disable the coin cell charger
unused
COINCHEN
UNUSED
3
R/W
—
0x00
0x00
7:4
PF4210
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© NXP B.V. 2018. All rights reserved.
Data sheet: technical data
Rev. 2.0 — 14 November 2018
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