Fully assembled board developed forperformance evaluation only,

not available for sale

Features• Qi v1.2.4-compliant wireless charging transmitter reference design following MP-

A2 topology• Supports Qi EPP-compliant mode up to 15 W• Supports up to 50 W with ST proprietary protocol (STSC)• Supports two coils working alternatively for positioning freedom• Supports USB-PD wall adapter input• Boost DC-DC:

– Key products: STWBC2-HP wireless charging transmitter SoC, STL20N6F7LV MOSFET

– Input: 4.1 to 24 V DC (from USB adapter)– Maximum input current: 3 A– Output: up to 38 V– Boost DC-DC controlled by STWBC2-HP SoC to convert USB adapter

input to the DC bridge voltage of the wireless charger LC tank– Short DC-DC by P-MOS on the control of STWBC2-HP SoC for the best

efficiency• Main bridge:

– Key products: STWBC2-HP wireless charging transmitter SoC, STL20N6F7LV MOSFET, STG719 analog switch

– Qi-compliant PID power control with frequency, duty-cycle, and voltage– Switching frequency: 110 to 145 kHz– ASK demodulation with voltage, current, and phase– FSK modulation– Protections for overvoltage, overcurrent, overtemperature, and

undervoltage– Q-factor estimation

• Auxiliaries:– Key product: STWBC2-HP wireless charging transmitter SoC– USB interface, embedded USB-PD stack– Embedded buck DC-DC to convert 5 to 27 V input to 3.3 and 5 V supply

voltages– Embedded charge pump to double the voltage and support the embedded

gate drivers– Reserved I²C interface to upgrade to Qi v1.3 with an external secure MCU

DescriptionThe STDES-50W2CWBC is a reference design that implements a Qi-compliantinductive wireless charger transmitter.

It supports two coils, which could work alternatively to increase the Rx positioningfreedom.

The solution supports Qi EPP-compliant mode up to 15 W, featuring an STproprietary protocol. It can also support 50 W or an even higher wireless powertransfer.

Product summary

50 W two-coil wirelesscharger transmitterreference design

STDES-50W2CWBC

Firmware for50 W two-coilwireless chargertransmitter basedon STWBC2-HP

STSW-50W2CWBC

Digital controllerfor wirelessbattery chargertransmitters

STWBC2-HP

N-channel 60 V,0.0046 Ohm typ.,20 A STripFET F7Power MOSFET

STL20N6F7

Low voltage 4Ohm SPDT switch STG719STR

Applications Wireless Chargers

50 W two-coil wireless charger transmitter reference design

STDES-50W2CWBC

Data brief

DB4673 - Rev 1 - February 2022For further information contact your local STMicroelectronics sales office.

www.st.com

The STDES-50W2CWBC is based on the STWBC2-HP high-integration, high-performance wireless charger system-on-chip.

It integrates: three pairs of half-bridge gate drivers, the dedicated DC-DC controllersthat support buck, boost and buck-boost topologies, the high-performance Q-factormeasurement hardware, the high-resolution main PWM controller, the dedicated Qicommunication modulator and demodulator, the USB-PD controller, the buck DC-DC,and the charge pump.

It is suitable for one-coil and multicoil solutions in multiple topologies.

The STDES-50W2CWBC is a fully assembled reference design developed forperformance evaluation only, not available for sale.

STDES-50W2CWBC

DB4673 - Rev 1 page 2/8

1 Schematic diagrams

Figure 1. STDES-50W2CWBC circuit schematic (1 of 4)

FAN CONTROL

STLINK V3

ESDESD

ESDESD

1DP1

2DM 1

3GND

6 DP2

5 DM 2

4 NC

D102

ECM F02-2AM X6

R102 10 R

R100 NP

D100

ESDA25P35-1U1M

R101 10 R

B12GNDB11RX+1B10RX-1B9VBUSB8SBU2B7

B5B4

A12

B3

SBU1VBUSRX-2RX+2GND

B2B1

A1 GNDA2

D-2D+2CC2

VBUSTX-2

TX+2GND

TX+1A3 TX-1A4 VBUSA5 CC1A6 D+1A7 D-1A8A9

A10A11

GN

D1

GN

DG

ND

2G

ND

GN

D3

GN

D

B6

GN

D4

GN

D

SH

1G

ND

SH

2G

ND

SH

3G

ND

SH

4G

ND

J100632723300011

R1070 R

R1060 R

R103 NP

C100

X7R50V100NF

D104BAT30KFILM

NTR4003NT1G 3D

1 G

2S

Q100N-M OSR108

0 R

C101

X7S50V

10UF C102

X7S50V

10UF

TP101

TP100

TP102

TP103

2 1

3

D103ESDALC6V1M 3

C104

X7R50V33NF

24

810

1357911

6

131214

J101

FTSH-107-01-L-DV-K-A

VIN

USB_DP

USB_DM

USB_D+USB_D-

UART_TX

UART_RX

USB_D+USB_D-

USB_CC2

USB_CC1

VBUCK

FAN

3V3

SW DIOSW CLK

UART_RXUART_TXNRESET

DB

4673 - Rev 1

page 3/8

STDES-50W

2CW

BC

Schematic diagram

s

Figure 2. STDES-50W2CWBC circuit schematic (2 of 4)

Truth TableIN Switch S1LH

Voltage doubler

Additional NTC

RING_SNS Switch

QF_DRV Switch

C21150V X7R

330NF

C21350V X7R

330NF

R21910 R

1 X1 3X2

2C

OVE

R2C

OVE

R1

4

Y 20016M HZ-10PPM -8PF

R205 NP

C206

35VX5R

10UF

TP200

R204 10 K

R200 0R1

C203

X7R50V100NF

NTC

R20647 K

R20210 K

C21250V X7R

330NF

R218

3.3 K 1%

R20110 R

R203150 K

R217470 K

D206SOD523

BAT54KFILM

R20810 K

D204SOD523

BAT54KFILM

R209 10 K

/I2C

drive

rga

teBo

ostra

p

drive

rga

teBo

ostra

p

Main PWM

drive

rga

teBo

ostra

p

AnalogDemod

Q- F dr i ver

ControllerDCDCMai n PWM

PD/QC

Buck

USB

ISns

6V

DD

2LD

O_3

V3

3V

RE

F_A

4M

CU

_3V

38

MC

U_V

SS

1

60 USB_DM59 USB_DP

11 XTAL_OUT10 XTAL_IN

12 NRST

5LD

O_1

V8

46 LED1

47 LED2

27V

DD

_DR

23S

PI_

MIS

O24

SP

I_M

OS

I

21 UART_TX28HS1_BT

29HS1_GD30HS1_SW

31LS1_GD

36HS2_BT

35HS2_GD34HS2_SW

32LS2_GD

41G

ND

_DR

9B

UC

K_F

B

14B

UC

K_S

W

15B

UC

K_B

T

16V

IN

22 UART_RX

43G PIO_DR142G PIO_DR0

48 SW DIO49 SW CLK

25S

PI_

NS

S

1 IRQ

68A

GN

D

54BRG_VREF

20S

PI_

CLK

19 TEM PSNS

53BRG_ISNS_P52BRG_ISNS_M

50B

RG

_VS

NS

62I2

C_S

DA

6

STWBC2-HP 3I2

C_S

CL

13P

GN

D

55BRG_IDEM

56BRG_FT_S57BRG_FT_R

7M

CU

_VS

S

64RING_FT_S65RING_FT_R

66Q

F_D

RV

69E

PA

D

33DCDC_SNS

17 VIN_ISNS_P18 VIN_ISNS_N

26V

DO

UB

_SW

37HS3_BT

38HS3_GD39HS3_SW

40LS3_GD

44GPIO_DR245GPIO_DR3

58 CC161 CC2

67RING_SNS

51D

CD

C_F

B

U200

R2071%47 K

D205SOD523

BAT54KFILM

C200NP

L200

10uH

D200

RB541VM -40

D201VDD_DRVDD_DR

RB541VM -40

C216

X7R50V10NF

C221

C0G50V8.2PF

C222

C0G50V8.2PF

C227

X7R50V10NF

C208

C0G50V1NF

C202

X5R50V470NF

C215

X7R

25V100NF

C217

X7R25V100NF

C218

X7R25V100NF

C223

X7R25V100NF

C224

X7R25V100NF

C228

C0G50V33PF

C220 X7R

100V1NF

R220

0 R

NTC

R21147 K

R210150 K

R213470 K

C225

X7R50V10NF

1 IN2 VCC3 GND

6S25D4S1

U202

STG719STR

C226

X7R25V100NF R222

3.3 K 1%

R2231%47 K

C229

C0G50V33PF

C230 X7R

100V1NF

D3

1 G

2S

Q202N-M O S2N7002

D3

1 G

2S

Q201N-M OS2N7002

R2284.7 K

R2274.7 K

C204

16V

10UFX5R C236

X7R25V100NF

C201

X5R6.3V4.7UF

C234NP

C235

X5R6.3V4.7UF

C233NP

R212 2.2R

R225 2.2R

R226 2.2R

C209X7R100V

5.6NF

3 D

1G

S 2Q200

N-M OS

1 IN2 VCC3 GND

6S25D4S1

U201

STG719STR

C237

X7R25V100NF

C231X7R100V

5.6NF

D 3

1G

2 S203BAT54KFILMQ

N-M OS

D208

BAT54KFILM

C214X7R50V10NF

C207

X7R25V100NF

C238

X7R6.3V1UF

C239NP

C210

X7R50V100NF

4 OUT

5 VCC

3IN-

1IN+

2G

ND

U203LM V321ILT

R229 10 K R2300.1%

330 K

C240

COG 50V

1NF

R231

0.1%

1.2KR232

0.1%

9.1K

C241

X7R50V100NF

C242

X7R50V100NF

R233

0.1%5.6K

R234

0.1%

330 K

C243

X7R50V100NF

J201

1234

D203GREEN

D202RED

D207

R235 100 R

R236 100 R

D209GREEN

R237

4.7 K

VBUCK

3V3

3V3

3V3

VBUCK

VIN

VDCDC

USB_DPUSB_DM

SW DIOSW CLK

UART_TXUART_RX

SW _HS2

G D_LS2

NRESET

USB_CC2USB_CC1

GD_HS1SW _HS1

GD_LS1

G D_HS2

GD_HS3SW _HS3

GD_LS3

BRIDGE_ISNS_P

RING_NODE1

I2C

_SC

LI2

C_S

DA

VIN_ISNS_NVIN_ISNS_P

SW _HS1

FA

N

LED1

LED2

3V3

TEM P

TE

MP

TANK1_SELTANK2_SEL

TANK1_SEL

RING_SNS

RING_NODE2

RING_SNS

TANK1_SEL

TANK2_SEL

QF_SHORT

QF

_DR

V

VBUCK

BRIDGE_ISNS_N

3V3 3V3

I2C_SCLI2C_SDA

1V8

1V8

RING_NODE1TANK1_SEL

RING_NODE2

QF_DRV

QF_SHORT

VBUCK

VREFVREF

VREF

3V3 VREF

BRIDGE_ISNS_P

DC

DC

_SH

OR

T

3V3

I2C_SCLI2C_SDA

VBUCKVBUCK

LED1

LED2

LED

3

3V3

LED3

Switch S2

OFF

OFFON

ON

/SPIGPIO

UART

GPIO

DB

4673 - Rev 1

page 4/8

STDES-50W

2CW

BC

Schematic diagram

s

Figure 3. STDES-50W2CWBC circuit schematic (3 of 4)

DC-DC BOOST SYNCHRONOUS

DC-DC SHORT

R30410 K

R302

0 R

R301

0 R

GS

D

5

4

16 7 8

2 3

Q301STL20N6F7

C302

X7R50V

100NF

R303

10 K

R30510 R

GS

D

5

4

16 7 8

2 3

Q300STL20N6F7

R300

0.010R/2W

C312NP

C313

C0G50V1NF

L300

3.3uH

R30610 R

C315

X7R50V

10NFR307

10 R

C309

X7R50V

100NFC314

X7R50V

10NFC310

50VCOG

1NF

R410100 K D400

10V

G

D

S

5

4

16 7 8

2 3

Q404P-M OS

10K

10K

1

23

Q405NPN

R411 10 K

C304

X7S50V

10UF + C30847UF50V

VIN

GD_HS1

GD_LS1

VIN

_IS

NS

_P

VIN

_IS

NS

_N

SW _HS1

SW _HS1

VDCDC

VIN

DCDC_SHORT

VBRIDGE

DB

4673 - Rev 1

page 5/8

STDES-50W

2CW

BC

Schematic diagram

s

Figure 4. STDES-50W2CWBC circuit schematic (4 of 4)

GND POWER

Derating >7uF at 20V

C419-C420-C421-C422

coil Qi-MPA2 10uH

R406NP

R41310 K

R402NP

L4001uH

R403 0 R

R4080.010R 0.1% 1W

R4040 R

C400

X7R50V100NF

GS

D5

41

6 7 8

2 3

Q400STL20N6F7

R4000 R

R401NP

GS

D

5

4

1

8 7 63 2

Q401STL20N6F7

R41510 K

R412

10 K

R414

10 K

GS

D

5

4

1

8 7 63 2

Q403STL20N6F7

R407 0 RGS

D

5

4

16 7 8Q402

2 3

STL20N6F7

C406

0402NP

C414NP

C413NP

GS

D

5

4

1678

23

Q406STL20N6F7

GS

D

5

4

1678

Q407

23

STL20N6F7

C411

NP

R418

NP

R221 0R

R224 0R

C232DNP50VC0G

GS

D

5

4

1

876

32

Q409

STL20N6F7

GS

D

5

4

1

876

32

Q408STL20N6F7

R424DNP1206

C404

X7S100V

DNP

R420DNP1206

C401

X7S100V

DNP

R416 10K R421 10K

C402

C0G50V1NF

D401

1N4148W S C418

X7R50V10NF

R42247K

R423 10K R425 10K

C423

C0G50V1NF

D402

1N4148W S C425

X7R50V10NF

R42847K

Q411BC856B Q412

BC856B

C431

X7R50V100NF

C432

X7R50V100NF

C433

X7R50V100N

1

coil Qi-MPA2 10uHTP401 TP400

1

C407C0G 100V

100NF

1

TP403

1

TP404

C408 100NFC0G 100V

C409 47NFFC0G 100V

C410C0G 100V

100NF

C412C0G 100V

100NF

C415 47NFC0G 100V

C419

X7S50V

10UFC420

X7S50V

10UFC421

X7S50V

10UFC422

X7S50V

10UF

10K

10K1

23

Q410NPN

10K

10K1

23

Q413NPN

VDCDC

G D_HS3

GD_LS3GD_LS2

GD_HS2

BRIDGE_ISNS_P

SW _HS2 SW _HS3

RING_NODE1

BRIDGE_ISNS_N

RING_NODE2

TANK1_ON

TANK2_ON

TANK1_SEL

VDD_DR

TANK1_ON

TANK2_SEL

VDD_DR

TANK2_O N

VBRIDGE

TANK1_SW

TANK2_SW

TANK1_SW TANK2_SW

DB

4673 - Rev 1

page 6/8

STDES-50W

2CW

BC

Schematic diagram

s

Revision history

Table 1. Document revision history

Date Revision Changes

28-Feb-2022 1 Initial release.

STDES-50W2CWBC

DB4673 - Rev 1 page 7/8

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© 2022 STMicroelectronics – All rights reserved

STDES-50W2CWBC

DB4673 - Rev 1 page 8/8