DS2712 Maxim Integrated Products, Inc., DS2712 Datasheet - Page 9

• Manufacturer Part Number: DS2712
• Description: Loose Cell Nimh Chargers
• Manufacturer: Maxim Integrated Products, Inc.

DS2712 Parallel Charge Configuration with Switch-Mode Charge Current Regulation
The example in Figure 5 uses the DS2712 to regulate charge current as a switching (buck) regulator. ICHG is set
to 2A using RSNS = 0.056W. The effective charge current for each cell is ICHG x 0.484 = 968mA. The CSOUT
comparator output switches OFF when the voltage across the sense resistor goes above 0.125V and back ON
when the voltage drops below 0.100V. In this mode, the operating frequency is determined primarily by the value of
the inductor, the hysteresis, the input voltage, and the voltage on the cells. In some cases, a damping network may
be required to prevent overshoot with the batteries removed.
Figure 5. PARALLEL CONFIGURATION WITH SWITCH-MODE CURRENT
REGULATION (DS2712 ONLY)
GND
+5V
C1
47u
47uF
10K
1u
270
270
680
FCX718
FCX718
100
47uHy
10K
150
FCX718
100
CC1
CC2
LED1
VSS
LED2
CSOUT
VN1
VN0
DS2712
10
DMSEL
0.1
THM2
THM1
CTST
VDD
TMR
9 of 14
VP2
VP1
ICHG
10k
10k
100k
75k
103AT-2
103AT-2
RSNS
0.056