DS1339 I

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TRICKLE CHARGER REGISTER (10h)

The simplified schematic in Figure 5 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 on

1010 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

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

DS0

ROUT1

ROUT0

X

X

X

X

0

0

X

X

Disabled

X

X

X

X

1

1

X

X

Disabled

X

X

X

X

X

X

0

0

Disabled

1

0

1

0

0

1

0

1

No diode, 250

Ω resistor

1

0

1

0

1

0

0

1

One diode, 250

Ω resistor

1

0

1

0

0

1

1

0

No diode, 2k

Ω resistor

1

0

1

0

1

0

1

0

One diode, 2k

Ω resistor

1

0

1

0

0

1

1

1

No diode, 4k

Ω resistor

1

0

1

0

1

0

1

1

One diode, 4k

Ω resistor

0

0

0

0

0

0

0

0

Initial power-up values

Warning: The ROUT value of 250

Ω must not be selected whenever V

The user determines diode and resistor selection according to the maximum current desired for battery or super

cap charging. The maximum charging current can be calculated as illustrated in the following example. Assume

would therefore be calculated as follows:

charge current decreases.