4
dc705af
DEMO MANUAL DC705A
Quick start proceDure
EVALUATION
Undervoltage Lockout Feature
• Increase the input power supply to approximately 3.8V
(battery simulator power supply set for 0V).
The charger output voltage and charge current should
be 0V. All three LEDs should be off. The charger is in
shutdown due to the undervoltage lockout feature.
Trickle Charge Current
• Increase the input voltage to 5V and keep the battery
simulator power supply at 0V.
The CHRG and ACPR LEDs should now be on, and the
FAULT LED should be off. The charger output voltage
(V
BAT
) should be approximately 240mV, and the charge
current should be about 100mA (10mV on the charge
current DVM). This is the trickle charge mode for a
deeply discharged battery. Typically, a battery that has
not been charged for a long time.
Constant Current Charge
• Starting at 0V, slowly increase the battery simulator
power supply (V
BAT
), observing the charger’s output
voltage on the DVM.
When the charger’s output voltage exceeds approxi
-
mately 2.45V, the charger will suddenly enter the con-
stant current portion of the charge cycle, resulting in an
abrupt
jump in the charge current to the programmed
value of approximately 1.0A (100mV on the charge
current DVM). This is
constant current mode.
Move jumper JP2 to the upper position (0.5A) to reduce
the charge current (I
BAT
) to 500mA, resulting in a read-
ing of approximately 50mV on the charge current DVM.
Move the jumper back to the original position.
VPROG Verification
• With 1.0A charge current flowing into the battery simu
-
lator, measure
the current monitor pin voltage V
PROG
.
This voltage is proportional to charge current with 1.5V
indicating full programmed current (1.0A).
Constant Voltage Charge
1. Continue slowly increasing the battery simulator power
supply, thus simulating a battery accepting charge.
The charge current should remain at the programmed
value of 1.0A until the charger output voltage is within
approximately 10mV of the of the preset charge volt-
age, at which time the charge current will begin to de-
crease. This is the beginning of the constant voltage
portion of the charge cycle.
2. Continue slowly increasing the battery simulator power
supply until the charge current drops to approximately
200mA (20mV on the charge current DVM), then read
the charger output voltage. This reading is the charger
float voltage which should be 4.2V ±40mV.
Shutdown
1. Move the SHDN/CHRG jumper JP1 to the upper posi
-
tion.
This shuts the charger down dropping the charge cur-
rent to 0mA. This is the shutdown mode.
2.
Move the jumper back to the original location.
Charge LED, C/10 Charge Near Complete
• Continue to slowly increase the battery simulator power
supply while observing the CHRG LED. The LED will
go out when the charge current drops to approximately
10% of the programmed charge current of 1.0A. This
verifies that the C/10 output is operating correctly.
NOTE: The LED current drops from approximately 10mA
when the LED is on, to approximately 25µA when the
charge current drops to 10%, and drops to 0µA after
the timer has timed out. (3 hours when a 0.1µF timing
capacitor is used).
At C/10, when the CHRG LED goes out, the battery is
about 94% charged. The charger will continue charging
for 3 hours (0.1µF timing capacitor) then stop, at which
point the battery is 100% charged.
