Analog Integrated Circuit Device Data

22

Freescale Semiconductor

18730

FUNCTIONAL DEVICE OPERATION

OPERATIONAL MODES

VG GENERATOR

Figure 10. Circuit when using a Step-Up Converter

When WAKE (int) goes High from Low, the start-up circuit

raises the VB voltage and outputs it to VGATE, then outputs

the VGATE voltage when PGOOD1 (int) goes High. The

charge pump circuit can be used for both Ni_mh and Li_ion

by setting the necessary registers. The charge pump circuit is

disabled by default.

The VGATE voltage can be set in the range of 6 V to 4.5 V

according to the combination of VGATESEL1 and 2 pin

connections. Refer to Table 16, VGATE Voltage Settings and

VGATESEL1 and 2 Pin Connection on page 23 for the VG

voltage settings.

When using a charge pump, please refer to Figure 11.

L

L

L

L

L

H

X

X

2.091

L

L

L

L

H

L

X

X

2.102

L

L

L

H

L

L

X

X

2.125

L

L

H

L

L

L

X

X

2.170

L

H

L

L

L

L

X

X

2.260

H

L

L

L

L

L

X

X

2.440

H

L

L

L

L

H

X

X

2.451

H

L

L

L

H

L

X

X

2.462

H

L

L

H

L

L

X

X

2.485

H

L

H

L

L

L

X

X

2.530

H

H

L

L

L

L

X

X

2.620

H

H

H

H

H

H

X

X

2.800

Notes

34.

All combinations of input are not included.

35.

The SREG1 and 3 output voltages are determined by the combination of external resistances connected to

SREGC1 and 3 (65.14K

Ω between SREGO1 and SREGC1, 34.86KΩ between SREGC1 and GND, 73.84KΩ

between SREGO3 and SREGC3, and 26.16K

Ω between SREGC3 and GND).

Table 14. Output Voltage of SREG3

B7

B6

B5

B4

B3

B2

CP Off

EXTG On

VBATT

VGATE

Step-Up

Pre Driver

SWGATE

VBATT

VGATE

GNDGATE

VG_select

VG_duty

VGATE

VGATE

Start Up