Semtech TSWIRX-LI-EVM User manual

www.semtech.com
WIRELESS CHARGING
User Guide
TSWIRX-LI-EVM
Wireless Charging Receiver
with Li-ion Battery Charger
(Rev. 2.00)

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Introduction
The Semtech TSWIRX-LI-EVM is an evaluation platform for the test and experimentation of a wireless
charging receiver based on the Semtech TS51223 fully-integrated IC for Wireless Power Receiver and
SC810 linear sigle-cell Li-ion battery charger. This evaluation module, in conjunction with its compatible
transmitter TSWITX-G2- EVM, provides a complete system solution for low power transmission, receiving
and charging for wearable devices.
Objectives
The objective of this User Guide is to provide a fast, easy and thorough method to experiment with and
evaluate the Semtech solutions for wireless charging systems. Sufficient information is provided to
support the engineer in all aspects of adding wireless charging support to their products. Semtech offers
a range of solutions to meet the needs of a wide range of system developers. Developers are provided
with all the information on how this EVM was built as a starting point for their own designs based on the
TS51223 and SC810.
Table of Contents
Wireless Charging Concepts....................................................................................................2
Product Description .................................................................................................................3
Standard Use ..........................................................................................................................4
Documentation ........................................................................................................................6
A. Block Diagram..............................................................................................................6
B. Schematic....................................................................................................................7
C. Bill Of Materials “BOM”.................................................................................................9
D. Board Layout..............................................................................................................10
E. Board Layers..............................................................................................................11
FAQs.....................................................................................................................................12
Next Steps.............................................................................................................................13

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Receiver
Transmitter
Control
Electromagnetic
Flux
Controller CoilDriver
Power
Supply
Supply
Regulation Rectifier
End
Equipment
Power
Wireless Charging Concepts
Wireless power transfer is, essentially, a transformer. Power is provided to a primary coil which produces
an electromagnetic (EM) field. In this field, a secondary coil is placed. The EM field induces a current into
the secondary coil, providing power to whatever it is connected to.
However, unlike a conventional power transformer that operates at line frequencies and requires an iron
core for efficiency, low power wireless power systems for wearable devices have been designed to
operate in the 1 MHz range, and thus can perform efficiently with an air core. As such, the primary and
secondary windings, if closely spaced, can be in separate devices, the primary being part of a transmitter
and the secondary within a receiver. This implementation can also be described as a radio broadcast
process, and as such, these transformer coils can also be seen as antennas with equal validity, and the
two terms will be used interchangeably in this text.
Wireless power systems differ in another major aspect from conventional transformers, in that they are
intelligently managed. A transmitter will only provide power when a receiver is present, and only produce
the amount of power requested by the receiver. The intelligent management of the wireless power
transmission process is achieved though the programming of the transmitter-resident TS80002, which
first searches for a receiver. Once found, the receiver informs the transmitter of its power requirements,
and transmission begins. The system then verifies the right amount of power is being sent. The receiver
continually provides ongoing requests for power to maintain the transaction. If the requests cease, the
transaction terminates. Via this protocol, even complex charging patterns can be supported, as the
transmitter can provide varying amounts of power at different times, as requested by the receiver. Should
the receiver require no further power, such as when a battery charge is completed, it can request no
further power be sent, and the transmitter will reduce its output accordingly.
Wireless power systems have been broken into three basic power categories. “Wearable” devices, such
as headsets, wrist-band devices, medical sensors, and so forth - all operate in the low power range, up to
5 watts. Medium power devices, in the 5- to 15-watt range, include most handheld devices, such as cell
phones, tablets, and medical electronics. High power wireless systems are intended to support devices
such as power tools, radio controlled (“RC”) devices such as drones, and other equipment requiring 15 to
100 watts of power.

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Product Description
The The TSWIRX-LI-EVM Evaluation Module is coupled with its compatible transmitter module, the
Semtech TSWITX-G2- EVM, to form a complete wireless power transmission system, to directly chare a
single cell Li-ion battery for approximately 300mA of charging current.
Those who wish to develop their own board, or integrate this functionality into an existing system can use
the EVM as a starting point for their design, as it demonstrates a working model from which to proceed.
Toward this end, all documentation for the EVM is provided to make the process as efficient as possible.
The key technology in the EVM is the Semtech TS51223, which is a fully-integrated wireless power
receiver for low-power, wearable applications that require a space-saving solution. Its 1 MHz switching
frequency enables the use of small inductive components resulting in minimal board space and reduced
costs. It integrates a wide range of protection circuitry including input supply under-voltage lockout, output
voltage soft start, current limiting, and thermal shutdown. The SC810 is a linear sigle-cell Li-ion battery
chager, which can provide a programmable charge current and constant 4.2V 1% regulation.
Once the system is set up and working, a selection of tests and activities will be described that the
evaluator can choose to perform.

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Standard Use
The TSWIRX-LI-EVM is easy to set up and use. Connect a USB cable from any USB port capable of
driving up to 2 watts (most PCs will suffice) to the USB port on the TSWITX-G2- EVM. On application of
power, its green LED should light, indicating the board is now active.
At this point, the transmitter EVM is ready to transmit power. A few times each second, the transmitter
emits a ‘ping’ of energy in search of a compliant receiver in range.
When in range, the receiver is powered by the ping sufficiently to be able to announce its presence to the
transmitter, and a transaction begins. The transmitter provides a small amount of power to the newly
discovered receiver, so it can tell the transmitter what its power requirements are.
At the completion of this handshake, the transmitter begins providing the requested power. During power
transfer, the receiver continuously communicates with the transmitter, actively directing the process. In
this way, it is assured that power is only sent when and how it is required by an available and desirous
receiver – and in the way that is compatible with the requirements of the receiver. If required, a receiver
can actively increase or decrease its power request, and the transmitter will act accordingly. As such,
equipment with complex charging requirements can be precisely supported and only the desired amount
of power is provided.

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EVM Receiver Tests
A variety of tests can be performed with the use of the TSWITX-G2- EVM transmitter module.
Connect a USB cable from any USB port capable of driving up to 2 watts (most PCs will suffice) to the
USB port on the TSWITX-G2- EVM. On application of power, its green LED should light, indicating the
board is now active.
In order to use the TSWIRX-LI-EVM as a target receiver, simply place the receiver over the target circle
(the ‘primary coil’ or ‘transmitter antenna’) on the transmitter EVM module, then connect a battery to the
J2 of receiver. Connect a DC voltmeter across the VOUT+ and GND pins to monitor the voltage, and a
DC ammeter in series with the VOUT+ line to monitor the chaging current. Set levels to allow for up to 10
volts and 1 amp to be observed.
The LED should be light green, which indicate charging begins after a valid charging input is applied and
the VIN pin is great than UVLO level.
J4 jumper is for ENB pin input select. The ENB pin is a tri-level logical input that allows select of 3 beviors:
1) ENB to gound (jummer pin2-3), charging enabled with float-charing after termination;
2) ENB float (no jummper), charing enabled with float-charing disabled and battery monitoring at
termination;
3) ENB to high (jumper pin1-2), charging disabled.
The CC mode is active when battery voltage is above VTpreg and less than Vcv. The programmed CC
regulation fast-charge (FQ) current can be set through IPRGM resistor (IFQ=0.204/RIPRGM). The default
current set is 250mA (IPRGM=8.06Kohm).

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Documentation
The following sections document the hardware design of the TSWIRX-LI-EVM. This information can be
used to better understand the functionality of the design, as well as assist in creating your own hardware
solution based on this design
A. Block Diagram
The TSWIRX-LI-EVM may be divided into a number of sub-blocks as show in the diagram below:
Antenna: Transmit – primary coil providing power to the receiver; part of TSWITX-G2- EVM
Antenna: Receive – secondary coil in the flux field of the transmit antenna; part of the 1 MHz resonant
tank
Rectifier – converts AC voltage from the antenna to positive values; FET based for high efficiency
conversion
Regulator - based on the TS51223; converts rectified input to regulated 5v output; includes protection
circuitry
Comm. Generator - produces the ‘handshake’ signal telling the transmitter to provide power
Comm. Modulator –– sends the handshake signal to the transmitter
Battery/Load – end equipment to be powered by the wireless receiver

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B. Schematic
Below are two copies of the schematic for the TSWIRX-LI-EVM. The first will be best when viewed on-
screen, as it is normally oriented and can be zoomed in on for readability. The second will allow better
use in print-out form, as the landscape orientation allows a larger image to be provided. For each,
annotation has been added to indicate which part of the block diagram each component is a member of.
10nF
50V
C4 22uF
25V
C2
GND
47nF
C5
22uF
10V
C8
100nF
25V
C3
GND
GND
4.7uH
L1
GND
1nF
50V
C6 1nF
50V
C7
10K
R3 46K
R1
GND
NP
C1
PDC 1
FREQ 2
ALERT 3
MOD_CFG 5
MOD_EN 4
GND 6
J3
External MCU (Optional)
75K
R2
4.7K
R4
PDC
GND
+
1
-
2Out
J2
BATTERY
VAC1
A1 PDC A2
SW C2
BST B4
GND B1
PDC B2
SW C3 COMM1
A3
GND C1
SW C4
FREQ
D3 FB A4
GND D1
PDC D2
ALERT
B3
MOD_CFG
D4
VAC2
E1 PDC E2
COMM2
E3
MOD_EN
E4
U1
TS51223 GND GND
47nF
C12
GND
GND
60K
R5
GND
22uF
10V
C9
X5R capacitors. Will only have 15-20% of the rated capacitance at 5V.
Some can be omitted if the load has capacitance.
VAC1
VAC2
PDC
SW
FB
FREQ
ALERT
MOD_EN
MOD_CFG
RX COIL AC1
AC2
8.06K
R8
10K
R6
GND
GND
2.2uF
10V
C20
GND
1
2
3
J4
Jumper
GND
VIN
1
STATB
2
GND
3IPRGM 4
BAT 5
ENB 6
PAD7
U2
SC810
LED1
GREEN
22uF
10V
C10 22uF
10V
C11
GND GND

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10nF
50V
C4 22uF
25V
C2
GND
47nF
C5
22uF
10V
C8
100nF
25V
C3
GND
GND
4.7uH
L1
GND
1nF
50V
C6 1nF
50V
C7
10K
R3 46K
R1
GND
NP
C1
PDC 1
FREQ 2
ALERT 3
MOD_CFG 5
MOD_EN 4
GND 6
J3
External MCU (Optional)
75K
R2
4.7K
R4
PDC
GND
+
1
-
2Out
J2
BATTERY
VAC1
A1 PDC A2
SW C2
BST B4
GND B1
PDC B2
SW C3 COMM1
A3
GND C1
SW C4
FREQ
D3 FB A4
GND D1
PDC D2
ALERT
B3
MOD_CFG
D4
VAC2
E1 PDC E2
COMM2
E3
MOD_EN
E4
U1
TS51223 GND GND
47nF
C12
GND
GND
60K
R5
GND
22uF
10V
C9
X5R capacitors. Will only have 15-20% of the rated capacitance at 5V.
Some can be omitted if the load hascapacitance.
VAC1
VAC2
PDC
SW
FB
FREQ
ALERT
MOD_EN
MOD_CFG
RX COIL AC1
AC2
8.06K
R8
10K
R6
GND
GND
2.2uF
10V
C20
GND
1
2
3
J4
Jumper
GND
VIN
1
STATB
2
GND
3IPRGM 4
BAT 5
ENB 6
PAD7
U2
SC810
LED1
GREEN
22uF
10V
C10 22uF
10V
C11
GND GND

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C. Bill Of Materials “BOM”
Below is a listing of the parts used in the TSWIRX-LI-EVM. Note that only a few dozen components were
required to implement the complete receiver solution. An excel spreadsheet file with this information is
available on the Semtech website as an added convenience.
SN Designa-
tor Description Footprint Manufac- turer
Manufactur-
erCode
Quanti-
ty
1
C1
NP
0402
NP
2
C2
0805 22uF 25V
X5R
0805
1
3
C3
0402 100nF 25V
0402
1
4
C4
0603 10nF 50V
X7R
0603
1
5
C5, C12
0402 47nF 10V
0402
2
6
C6, C7
0402 1nF 50V
0402
2
7
C8, C9,
C10, C11
0603 22uF 10V
X5R
0603
4
8
C20
0603 2.2uF 10V
X5R
0603
1
9
L1
0805 4.7uH
0805
TDK
VLS201612CX
-
4R7M
1
10
LED1
0603 LED REEN
0603
1
11
R1
0402 46K4
0402
1
12
R2
0402 75K
0402
1
13
R3, R6
0402 10K
0402
2
14
R4
0402 4.7K 0402
1
15
R5
0402 60K4 0402
1
16
R8
0402 8.06K
0402
1
17
U1
Wireless
Power
Receiver
WCSP40P180X2
20-20VN
Semtech
TS51223
1
18
U2
Li
-
ion charger
MLPD
-
UT6
Semtech
SC810
1
19
AC1,AC2 Coil E&E
ES Y31
-
60150F
1
20
J2
HDR 1×2Pin
2.54mm Male HDR 1×2 1
21
J4
HDR 1×3Pin
2.0mm Male HDR 1×3 1
22
J3
HDR 1×6Pin
2.0mm Male HDR 1×6 1

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D. Board Layout
The diagram below shows the locations of the components used in the TSWIRX-LI-EVM PCB.

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E. Board Layers
The TSWIRX-LI-EVM PCB is based on a four layer design as shown below. The ground plane in layer
two is recommended to reduce noise and signal crosstalk. The EVM placed all components on the top of
the board for easier evaluation of the system. End product versions of this design can be made
significantly smaller by distributing components on both sides of the board. The Gerber files for this
artwork can be downloaded from the Semtech web page.
Top Layer Ground Plane
Signal Layer Bottom Layer

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FAQs
Q: What output voltage is provided by the TSWIRX-LI-EVM system?
A: The output is 4.2 volts for Li-ion charging, with a maximum charing current 250mA.
Q: Is the TSWIRX-LI-EVM compliant with Qi or another wireless transmission standard?
A: These low power wearable solutions are not based on existing standards in order to employ smaller
coils and other optimizations that better suit the low power system environment.
Q: Does the EVM part number represent something in particular?
A: Yes. The part number is broken into a prefix, main body, and suffix, separated by dashes. The prefix is
comprised of three two letter groupings that each help define the product represented. As such, the part
number can be read as follows:
Prefix characters:
1+2 = Company : TS = Triune/Semtech
3+4 = Environment : DM = Dual Mode I = earable Infrastructure
5+6 = Type : TX = Transmit RX = Receive
Mid-section = Device Voltage or Wattage
Suffix = Equipment t pe:
EVM = Evaluation Module
MOD = Production Module
Thus, the TSWIRX-LI-EVM is a Wearable Infrastructure, 5 volt Receiver Evaluation Module provided by
Semtech.
Q: Does the TSWIRX-LI-EVM implement Foreign Object Detection (FOD)?
A: FOD detection is an important protection in higher power systems, but in low power wearable
infrastructure systems there is no risk of overheating, rendering FOD management unnecessary.
Q: What if my questions weren’t answered here?
A: Go to the Semtech website as described on the next page. An updated FAQ for the TSWIRX-LI-EVM
is maintained there and may contain the answers you’re looking for. Your local Semtech FAE can also
assist in answering your questions.

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Next Steps
For more information on Wireless Power, go to the Semtech webpage at:
https://www.semtech.com/power-management/wireless-charging-ics/
You may also scan the bar code to the right to go to the above web page:
There you can find the downloadable copies of the schematic, BOM, and board artwork, as well as
additional information on how to obtain Semtech wireless power products, from the chip level all the way
to complete board modules, as your needs require.

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IMPORTANT NOTICE
Information relating to this product and the application or design described herein is believed to be reliable, however
such information is provided as a guide only and Semtech assumes no liability for any errors in this document, or for
the application or design described herein. Semtech the latest relevant information before placing orders and should
verify that such information is current and complete. Semtech reserves the right to make changes to the product or
this document at any time without notice. Buyers should obtain warrants performance of its products to the
specifications applicable at the time of sale, and all sales are made in accordance with Semtech’s standard terms
and conditions of sale.
SEMTECH PRODUCTS ARE NOT DESIGNED, INTENDED, AUTHORIZED OR WARRANTED TO BE SUITABLE FOR USE
IN LIFE-SUPPORT APPLICATIONS, DEVICES OR SYSTEMS, OR IN NUCLEAR APPLICATIONS IN WHICH THE
FAILURE COULD BE REASONABLY EXPECTED TO RESULT IN PERSONAL INJURY, LOSS OF LIFE OR SEVERE
PROPERTY OR ENVIRONMENTAL DAMAGE. INCLUSION OF SEMTECH PRODUCTS IN SUCH APPLICATIONS IS
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The Semtech name and logo are registered trademarks of the Semtech Corporation. All other trademarks and trade
names mentioned may be marks and names of Semtech or their respective companies. Semtech reserves the right to
make changes to, or discontinue any products described in this document without further notice. Semtech makes no
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purpose. All rights reserved.
© Semtech 2015
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