Continental Refrigerator D-WMI2020A User manual

D-WMI2020A_User_Manual_Rev4.docx
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USER MANUAL
WMI
Wireless Mobile Interface
D-WMI2020A
A2C166290
A3C011152
A3C017280
A2C166288
A3C011059
A3C011151
A3C017277

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1. System Overview
Continental Wireless Power Charger is developed for automotive applications under the
name WMI which includes three functions like:
- WPC: Wireless power charger
- NFC: Near field communication
The WMI module and their implementation in different variants inside the vehicle is depicted
in Fig. 1.
D-WMI2020A
Front console
Fig. 1 : WMI module and WMI automotive implementation inside the vehicle
1.1 WPC
WPC feature of the WMI uses Qi standard of Wireless Power Consortium (WPC) for
enabling wireless charging from a base station unit to mobile device. The power transfer
method is based on near field magnetic induction between coils.
1.1.1 System Overview
The WMI wireless charger provides power transfer from the internal coil to the smartphones'
battery. The power transfer technology is based on Qi standard operating with a fixed
frequency of 127.7kHz+/-6kHz.
1.1.2 WPC modes
A simple operational description of wireless power transfer can be summarized in two
operational modes. The first mode with a defined burst sequence allows the transmitter to
detect the smartphone Qi compliant. Then, the second mode allows the power transfer from
the WMI to the smartphone. Details of each operational mode are presented below:
1.1.2.1 Ping mode
In this operational mode, the WMI module transmits a short time carrier signal with a specific
pattern to detect a smartphone. When a mobile device is placed on the WMI, the
identification and the collection of configuration information is done. Based on that

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information, the transmitter creates a power transfer contract containing the maximum
power to be delivered to the load.
1.1.2.2 Charging mode
After “Ping mode”, the power transfer starts. In this operational mode, the transmitter sends
the carrier at a given level defined in the power contract in the operational “Ping mode”. The
WMI controls the power transferred to the smartphone, in response to the control data
messages sent by the smartphone.
1.1.2.3 Transmitter to receiver communications
The WMI transmitter communicates to the mobile device using Frequency Shift Keying, in
which the Transmitter modulates the Operating Frequency of the Power Signal.
1.1.3 WPC parameters
Bellow in table 1, the technical parameters of the WMI WPC feature are specified:
Parameters
Values
Carrier frequency
127.7 kHz
Frequency shift
+/- 6 kHz
Supply voltage
12V battery
Voltage supply range
9V < Vbat < 16V
Max. power consumption
35W (25W typ)
Product operating temperature range
Smartphone operating temperature range
-40°C < Temp < 85°C
-20°C < Temp < 60°C
WPC chipset brand
IDT
WPC litz coil
Single coil MPA19
according to Qi standard
WPC litz coil gain @ 127.7kHz
-107.1 dBi
Max. output power
15W
Max. current consumption
3.5A (2A typ)
Vehicle fuse protection
7.5A
Product weight
270 g
Dimensions (X/Y/Z in mm)
170/90/33 mm
Table 1: WMI WPC technical parameters.
The rated output power from the WPC coil is Max. 15W transferred to the load. The receiver
manages the wireless charger in order to guarantee stable 15W on the load.
1.2 NFC
NFC Reader used NFC (Near Field Communication) technology to enable the
communication between phones and cards with the vehicle, having user functions like, BT
pairing and Wi-Fi pairing.
The WMI integrates only one NFC transceiver at 13.56MHz connected via switches to an
internal NFC antenna and to an external antenna. Only one NFC antenna is fed at a given
time.

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Fig. 2 : WMI NFC block diagram
1.2.1 NFC Parameters
Bellow in table 2, the technical parameters of the WMI NFC feature:
Parameters
Values
Carrier frequency
13.56 MHz
Modulation type
Amplitude Shift Keying (ASK)
Data rate max.
848 kbps
Supply voltage
12V battery
Voltage supply range
9V < Vbat < 16V
Product operating temperature range
Smartphone operating temperature range
-40°C < Temp < 85°C
-20°C < Temp < 60°C
NFC chipset brand
NXP Semiconductors
NFC chipset model number
NCF3340EHN
Vehicle fuse protection
7.5A
Table 2: WMI NFC technical parameters.
1.2.2 NFC antennas
The NFC reader is composed of two antennas, internal and external antenna.
- The internal antenna is that one is implemented inside the WMI module.
- The external antenna is that one connected to the WMI module.
Fig. 3: NFC antennas of D-WMI2020A
1.2.2.1 NFC internal antenna:
Here bellow is shown the NFC antenna for High and Low WMI versions.

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Large Antenna PCB: NFC internal antenna trace on
antenna PCB is shown in green
Small Antenna PCB: NFC internal antenna
trace on antenna PCB is shown in green
Fig. 4: NFC Internal antennas
The electrical parameters of the NFC internal antenna are listed in the following table
Parameters
Values
Antenna type
Planar Printed Coil on PCB
Number of turns
3
Antenna Size
109mm x 43mm
Antenna Gain (dBi) @ 13.56MHz
Large antenna = -50.8 dBi
Antenna Gain (dBi) @ 13.56MHz
Small antenna = -51 dBi
Table 3: NFC internal antenna electrical parameters.