BQ2000 Datasheet, PDF (2/18 Pages) Texas Instruments – Programmable Multi-Chemistry Fast-Charge Management IC

bq2000
Pin Descriptions
SNS
VSS
LED
BAT
TS
Current-sense input
Enables the bq2000 to sense the battery cur-
rent via the voltage developed on this pin by
an external sense-resistor connected in se-
ries with the battery pack
System Ground
Charge-status output
Open-drain output that indicates the charg-
ing status by turning on, turning off, or
flashing an external LED
Battery-voltage input
Battery-voltage sense input. A simple resistive
divider, across the battery terminals, generates
this input.
Temperature-sense input
Input for an external battery-temperature
monitoring circuit. An external resistive di-
vider network with a negative tempera-
ture-coefficient thermistor sets the lower
and upper temperature thresholds.
RC
VCC
MOD
Timer-program input
RC input used to program the maximum
charge-time, hold-off period, and trickle
rate during the charge cycle, and to disable
or enable top-off charge
Supply-voltage input
Modulation-control output
Push-pull output that controls the charging
current to the battery. MOD switches high
to enable charging current to flow and low to
inhibit charging- current flow.
Functional Description
The bq2000 is a versatile, multi-chemistry battery-
charge control device. See Figure 1 for a functional block
diagram and Figure 2 for a state diagram.
TS
Voltage
Reference
Voltage
Comparator
BAT
ADC
PVD
ALU
OSC
Clock
Phase
Generator
Timer
Charge
Control
RC
Internal
OSC
Voltage
Comparator
LED
MOD
SNS
Figure 1. Functional Block Diagram
V_CC V_SS
bq2000BD.eps
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