IDT1339
REAL-TIME CLOCK WITH SERIAL I2C INTERFACE
RTC
Trickle Charger Register (10h)
Programmable Trickle Charger
The simplified “Programmable Trickle Charger” schematic shows the basic components of the trickle charger. The
trickle-charge select (TCS) bits (bits 4 to 7) control the selection of the trickle charger. To prevent accidental enabling, only
a pattern of 1010 on the TCS bits enables the trickle charger. All other patterns disable the trickle charger. The trickle
charger is disabled when power is first applied. The diode-select (DS) bits (bits 2 and 3) select whether or not a diode is
connected between VCC and VBACKUP. The ROUT bits (bits 0 and 1) select the value of the resistor connected between VCC
and VBACKUP. Table 6 shows the bit values.
Table 6. Trickle Charger Register (10h)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Function
TCS3 TCS2 TCS1 TCS0
DS1
0
DS0
0
ROUT 1 ROUT 0
X
X
X
1
1
1
1
1
1
0
X
X
X
0
0
0
0
0
0
0
X
X
X
1
1
1
1
1
1
0
X
X
X
0
0
0
0
0
0
0
X
X
0
0
0
1
1
1
1
0
X
X
0
1
1
0
0
1
1
0
Disabled
Disabled
Disabled
1
1
X
0
X
1
No diode, 250Ω resistor
One diode, 250Ω resistor
No diode, 2kΩ resistor
One diode, 2kΩ resistor
No diode, 4kΩ resistor
One diode, 4kΩ resistor
Initial power-up values
1
0
0
1
1
0
0
1
1
0
0
0
Warning: The ROUT value of 250Ωmust not be selected whenever VCC is greater than 3.63 V.
IDT® REAL-TIME CLOCK WITH SERIAL I2C INTERFACE
10
IDT1339
REV K 032910
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
