U2403B Datasheet, PDF (1/12 Pages) TEMIC Semiconductors – Charge Timer

Charge Timer
U2403B
Description
The U2403B is a monolithic, integrated-bipolar circuit
which can be used in applications for time-controlled,
constant-current charge. Selection of charge current
versus timing is carried out by using the external circuit
at Pins 2, 3 and 4. For high current requirement, an
external transistor is recommended in series with the
battery. To protect the IC against high power loss
(typically > 140°C), the oscillator is shut down when the
reference voltage is switched off (0 V). The latter also
takes place when there is a saturation caused by collector
voltage at Pin 1. When the overtemperature has
disappeared and the collector voltage at Pin 1 has
exceeded the supply voltage (V₁ > V_S), charge time
operation continues (see flow chart in figure 3).
Features
D Easy-to-run autonomous dual rate charger
D Constant charge current
D 3 h – 24 h charge time programmable
D Low cost dc regulator
D Overtemperature protection
D Charge-mode indication
D Operation starts at the moment of battery insertion
D Fast charge time-test mode
Applications
D Cordless telephones
D Low-cost battery-charge timer
D Entertainment
Package: DIP8, SO8
Block Diagram
Power
supply
AC/DC
Battery
inserted
LED₂
Charge
R₁
R₅
LED
LED₁
Ready
8
C₁
V_S
GND
6
7
94 8629
Charge mode
indicator
Power supply
V_S = 3.5 to 12 V
Test
mode
5 S_TM
í max
140°C
1
V₁
í
2
Shunt
Timer and control logic
V_Ref = 1.5 V/ 0.1 V/ 0 V
V_Ref
+
–
RC
oscillator
3
4
Sense
Osc
R₃
R₄
C₄
Figure 1. Block diagram with external circuit
TELEFUNKEN Semiconductors
Rev. A2, 14–Nov–96
1 (12)