#643 XKT-511 Wireless LED Module

Investigating a wireless LED power module based on the XKT-511 chip.

Build

Notes

I’ve seen a few wireless LED power modules for sale so decided to pick one up to find out how they have been designed. I picked a DC Remote Micro Receiver Wireless Power Supply Module wireless power supply coil module that uses the XKT-511 chip on the transmitter end and came with 3 LED modules.

module_1

After examining the module, it is quite straight-forward: the XKT-511 chip is fully integrated ASIC used to monitor and control the oscillation on the transmitting coil. It seems to only require 4 additional components:

two capacitors (input and output side)
two resistors forming a voltage divider for feedback control

The XKT-511 appears to be the latest generation of wireless power control technology from 深圳芯科泰半导体有限公司 Shenzhen Coretech Semiconductor Co., Ltd.. While they haven’t published the datasheet on their website, they have excellent customer service and provided me the full specs in response to an email.

module_3

Module Specs

From the aliexpress vendor page:

The combined kit (regulator, coil and LEDs) is designated the XKT515-09. The chip on the module is marked XKT-511.

The main parameters:

Transmitting voltage: 12V
The transmitting coil: 75mm*1mm
The receiving coil: 14.5mm
Sending and receiving distance: 45mm

They also offer additional LED modules.

module_2

XKT-511

The main problem I ran into is that while the XKT-511 chip is available for sale, I wasn’t able to find product information or a datasheet. I was able to find the XKT-511 chips for sale in various places such as this listing on taobao.

I figured it was produced by 深圳芯科泰半导体有限公司 Shenzhen Coretech Semiconductor Co., Ltd. who produce similar chips like the XKT-510. Although their website does not list it, I was pleasantly surprised when a simple email to them produced a quick reply with a full set of datasheet. Excellent service! They are in Chinese of course, but that is my problem;-)

Selected extracts from the datasheet:

Features

Small size，Packaged as SOP-8
High working frequency
High integration，Few peripheral devices
High output power
Wide range of applications
Control function can be designed freely
Under special design，It can control the working state of the receiving part
working voltage ：DC 3.3~18V
working frequency ：1KHz~3.5MHz
The coil can be printed PCB Board
The optimum state of quiescent current can be designed to be lower than 5mA。

SOP8 Pin Configuration

Pin	Label	Function
1	R	Frequency Modification Resistor
2	R	Frequency Modification Resistor/Voltage Monitor Resistor
3	Drive GND	Digital drive low voltage power ground
4	Load GND	Load ground (for function expansion use)
5	VIN	Load source
6	TEST	Working frequency test
7	VDD	Power supply (0-18V)
8	N/F	Control terminal, set high to work, set low to close output, can access custom control signals

Example Circuit 1

This example from the datasheet is I think identical to the circuit used in the XKT515-09 package I have.

Notes on the circuit:

designed for 5V power supply
The emission quiescent current is 60mA±10mA, the output power of this circuit is relatively large, and the coil area and distance determine the actual output power.
Transmitting circuit stability test method:
- power on the transmitting part, record the static current parameters, normally it should be 60mA±20mA (the maximum limit value is not more than 100mA).
- If the current deviation is not large, you can make fine adjustments by adjusting the number of coil turns.
- PS: If you are worried about the high temperature after the transmitter chip is damaged, you can string a resettable fuse in the power supply part as a short circuit protection.

example_circuit_1

Similar Products

The XKT-511 information is not widely available on the internet as yet. A search will likely yield results for the following chips. Be careful not to get confused - these chips are similar in function but quite different in the particulars:

XKT-412 - much older product also for wireless power transmission, usually paired with T5336 chip and many external passives. Circuit and datasheet widely available. appears to be the 1st generation product before a 2nd generation of XKT-5xx chips.
XKT-510 - appears to be a very similar, perhaps immediate precursor. Requires more external components and has a very different pinout than the XKT-511.
XKT-515 - allegedly similar to the XKT-511, but I haven’t seen the datasheet.
T3168 / XKT-3168 is a general-purpose receiving integrated circuit for wireless charging. It could be used on the receiving end of the XKT-511 transmitter.
XKT-R2 - appears to be the big broether of the XKT-511. DEsigned for high-voltage/high-current charging.

Construction

Here is my rough redrawing of the XKT-511 transmitter module. Note:

I haven’t measured the values of C1, C2; I am assuming they follow the example circuit from the datasheet
R2 measures about 75kΩ in-circuit, which matches the example circuit from the datasheet. The part appears to be labelled “098” (900MΩ?!!) but that doesn’t seem right.

schematic

Project Notes