10.2 Dual Charger - Panasonic G600 Technical Manual

10.2 Dual Charger

10.2.1 Circuit Description
A battery present is detected by the TH input, and battery type is detected by the S input. The S input is
open-circuit on a small battery, pulling the base of Q13 high, turning it off. The base of Q2 is pulled low through
R24, turning Q2 ON. This switches the extra control resistor VR1 into circuit, increasing the timer clock rate. VR2 is
used to control the clock rate when a large battery is connected.
The charging circuit is controlled by the current drawn by the handheld unit. If the handheld unit receives a call and
thus requires greater than 300mA, then it switches the charger off, only switching it back on again when the current
drops below 200mA. These current levels are controlled by VR3 (set the stop point) and VR4 (set the start point).
The power out for the handheld unit is protected by Q11, Q16, and Q5. When the power is connected, a small
current can flow through R27 and the bleed resistor R33. Through the potential divider R39 and R38, this turns Q5
ON, turning Q16 ON. Should the output CN2 become accidentally short-circuited the base of Q5 becomes low
turning Q5 OFF. This pulls the base of Q16 high, turning Q16 OFF and shutting off the power.
10.2.2 Adjustment Procedure
If any of the main components in the charger are replaced then the following procedure must be followed. The
procedure first adjusts the charge rate timer for each battery, followed by the control current levels for switching the
charger on and off.
Connect the charger as shown in the following diagram.
GND
Figure 1: Charger Connections
Adjust VR2 until the pulses on pin 3 of IC 2 have a period of 10mS ± 0.5mS. Open the switch S1 and adjust VR1
until the pulses have a period of 3.45mS ± 1.5mS.
With S1 closed connect a load of 300mA ± 5mA across the output that goes to the handheld unit. Adjust VR3 so
that clock pulses on pin 3 of IC 2 stop i.e. there is a steady level of 5V or 0V. Now reduce the load to 200mA ± 5mA
and adjust VR4 so that the pulses start again.
MCUK980101G8
Technical Guide
http://cxema.ru
+
S1
S
TH
10K
30 3W
Section 10
10 - 5
ACCESSORIES
10mS
600-1101
Revision 0
Issue 1