1
DEMO MANUAL
DC2554A-A-KIT/DC2554A-B-KIT
Rev. 0
DESCRIPTION
LTC4125 and LT3652HV
650mA Wireless Battery Charger
Demonstration Kit
DC2554A-KIT is a kit of the DC2556A transmitter,
featuring LT C
®
4125, the DC2555A-A/DC2555A-B receiver,
featuring LT3652HV. The DC2555A-A/DC2555A-B receiver
can charge a single Li-Ion battery at up to 650mA with
an air gap of 3.0mm to 12.0mm between the transmit
All registered trademarks and trademarks are the property of their respective owners.
PERFORMANCE SUMMARY
CONTENTS
BOARD PHOTO
and receive coils. The DC2556A transmitter supports
Optimum Power Search and Foreign Object Detection
features via LTC4125.
Design files for this circuit board are available.
Figure1. DC2556A Picture Figure2. DC2555A-A/DC2555A-B Picture
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
DC2556A Voltage Input I
VIN
≤ 2.5A 4.5 5.5 V
I
IN
DC2556A V
IN
Current V
IN
= 5V 2.5 A
V
BAT
DC2555A-A Battery Charge Voltage 4.12 4.2 4.28 V
V
BAT
DC2555A-B Battery Charge Voltage 3.53 3.6 3.67 V
I
BAT
DC2555A-A/ DC2555A-B Charge Current V
FB
= 3V 650 mA
AIR-GAP Separation Between L
TX
and L
RX
3.0 5.25 12 mm
KIT NUMBER TX BOARD TX PART NUMBER RX BOARD RX PART NUMBER RX OPTION
DC2554A-A-KIT DC2556A LTC4125 DC2555A-A LT3652HV Fixed 4.2V Float Voltage
DC2554A-B-KIT DC2556A LTC4125 DC2555A-B LT3652HV Fixed 3.6V Float Voltage
1 × DC2556A (LTC4125) Transmitter Demo Board
1 × DC2555A-A/DC2555A-B (LT3652HV) Receiver Demo Board (with 9.5mm (0.375’’) Nylon Standoffs, 5.25mm Gap)
4 × 12.5mm (0.375’’) Nylon Standoffs (8.25mm Gap)
4 × 15.9 mm (0.625’’) Nylon Standoffs (11.65mm Gap)
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DEMO MANUAL
DC2554A-A-KIT/DC2554A-B-KIT
Rev. 0
QUICK START PROCEDURE
Refer to Figure 3 to 5 for the proper measurement equipment
setup, DC2555A (for both -A and -B) mounting on DC2556A,
and follow the procedure below:
1. Place the DC2555A board atop the DC2556A board
by alignging the mounting standoffs (Figure3). This
should result in the transmit coil being direcly above the
receive coil, with the centers aligned. The DC2554A-A-
KIT/DC2554A-B-KIT ships with two additional standoff
sizes. This allows the air gap to be varied from 5.25mm
to 11.65mm.
2. Connect a voltage source PS1 and a 3Ω resistor
RBAT1 in parallel between the BAT and GND turrets
of DC2555A (Figure4). PS1 and RBAT1 make up the
battery emulator. Typical power supplies cannot sink
current. By adding a resistor across the power supply
inputs that draws more current than the maximum bat-
tery charging current, the power supply only sources
current even when the battery charge current is at its
maximum value.
3. If an ammeter is used to measure the charge current,
please be sure to use the external sensing by selecting
EXTS jumper and connecting a pair of cable from VSNS
and GND turrets to PS1 as Kelvin sensing connection.
If an ammeter is not needed, INTS can be selected and
Kelvin sensing connection is not needed.
4. Connect a power supply (PS2) between DC2556A VIN
GND turrets. DC2556A can also be powered through
Micro-USB cable to a 2.5A, 5V power source.
5. Set PS1 = 3.7V for DC2555A-A (set PS1= 3.2V for
DC2555A-B), PS2 = 5V and enable both power supplies
simultaneously. The DC2556A should start sweeping
the LTx current, looking for a receiver. When a valid
receiver is found, the LED sweeping will freeze until
the next search period. This is also indicated by the
DC2556A green status LED being turned on. The input
current monitor LED string will show the input current
percentage with respect to 2.5A current limit.
6. The DC2555A green LED string should be turned on,
indicating power is delivered to the load. If all the green
LEDs are lit, the LT3652HV on the DC2555A is deliver-
ing full programmed battery charge current, which is
650mA
in this demo.
7. The LTC4125 on the DC2556A keeps the transmit
power required by the receiver for about 5 seconds.
Then, the LTC4125 enters another search cycle to
check the receiver side power demand.
8. When the system is operating correctly, slide a piece of
blank PCB*, or coin between the transmit and receive coil.
The transmit current should immediately drop to 0A.
9. When test is done, turn off PS1 and PS2 simultaneously.
*Testing with a blank PCB of at least 10 cm
2
(1.5 IN
2
) of copper.
Figure3. DC2555A-A-KIT in Operation