ISL6253 Datasheet, PDF (8/22 Pages) Intersil Corporation – Highly Integrated Battery Charger for Notebook Computers

ISL6253
Typical Operating Performance (Continued)
Circuit of Figure 18, VDCIN = 20V, 4S2P Li-Ion Battery, T_A = 25°C, unless otherwise noted.
PHASE
10V/DIV
VVDDCCININ=2=0V20V
VVCCSSOONN=1=6.186V.8V
PHASE
10V/DIV
UGUGATAETE
UGATE
LGATE
2V/DIV
LGALTGEATE
t: 100ns/DIV
FIGURE 13. SWITCHING WAVEFORMS AT CONSTANT
CHARGE CURRENT MODE
INDUCTOR
CURRENT
0.5A/DIV
CHARGE
CURRENT
0.2A/DIV
1µs/DIV
FIGURE 14. SWITCHING WAVEFORMS AT TRICKLE CHARGE
MODE
1
0.96
0.92
VCSON = 12.6V
3 CELLS
VCSON = 8.4V
2 CELLS
0.88
VCSON = 16.8V
4 CELLS
0.84
0.8
0.76
0 0.5 1 1.5 2 2.5 3 3.5 4
CHARGE CURRENT (A)
FIGURE 15. EFFICIENCY vs CHARGE CURRENT
Functional Pin Descriptions
BOOT
Connect BOOT to a 0.1µF ceramic capacitor to the PHASE
pin and connect to the cathode of the bootstrap Schottky
diode.
UGATE
UGATE is the high side MOSFET gate drive output.
SGATE
SGATE is the AC adapter power source select output. The
SGATE pin drives an external P-MOSFET used to switch to
AC adapter as the system power source.
BGATE
BGATE power source select output. This pin drives an
external P-channel MOSFET used to switch the battery as
the system power source. When the voltage at the CSON
pin is higher than the AC adapter output voltage at DCIN,
BGATE is driven to low and selects the battery as the power
source.
LGATE
LGATE is the low side MOSFET gate drive output; swing
between PGND and VDDP.
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