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KMi: Interface Display for the KM2

KMi-series Datasheet © 2015 Thermoelectric Conversion Systems Limited Issue B – March 2016

KMi Series

Revised March 2016

Measurement Board to Display Voltage/Current Readings from the

KM2-series Converters for Thermoelectric Generators

Features Complements the KM2 series of MPPT converter

Interface between the KM2 and the Battery

Monitors Battery and TEG voltage and current

Two Temperature Measurements

Data displayed on the LCD and available through

analogue outputs

Quick Description The KMi interface display has been designed to work

exclusively with the KM2 series of maximum power point

tracking converters for thermoelectric generator(s). It

connects in series between the battery and the KM2 and between the TEG and the KM2 to monitor

and display both the battery voltage and current and the TEG voltage and current. Two thermistors

can be used to provide temperature measurement. Power is supplied to the KMi directly from the

battery. The KMi interface board can communicate through I2C.

Absolute Maximum Ratings Value

Min Max Unit

Input Voltage (open-circuit) -0.3 30 V

Output Voltage 10 20 V

Input power 0 Follow limit for KM2 W

Input Current 0 12 A

Operating Temperature -10 85 ˚C

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KMi: Interface Display for the KM2

KMi-series Datasheet © 2015 Thermoelectric Conversion Systems Limited Issue B – March 2016

Diagram of Connections The TEG + and – terminals should be connected to the TEG IN terminal block while the battery

terminals should be connected to the BAT IN terminal block, as shown in Fig. 1.

The KM2 converter pins version should be connected to the two 5x2-pin receptacles with the KM2’s

BAT header to J1 and the KM2’s TEG header to J2. Practically, both PCBs normally slot into each

other when both facing upwards (inductor and LCD on top).

The analogue outputs header JP4 provides, from left to right: GND, N/A, TEG current, TEG voltage,

battery current, battery voltage. Contact us for more information about these outputs.

The jumper J6 enables back light illumination of the display when the pin is set across BL and VCC.

Contact us about trigger and I2C functionalities.

Two thermistors can be connected to the cold (JP5, “Tc”) and hot (JP1, “Th”) mini screw terminals.

(See notes below).

Fig. 1: Diagram of connections for the KMi interface board.

Notes:

1. The 5-pin programming header should not be used by customers and it is not populated. 2. Two thermistor inputs are provided. We recommend NTC, 10 kΩ nominal impedance

Epcos B57703M103G40. These thermistors are rated -55C to 155C. 3. The 4-line display updates at 250ms intervals to show the TEG voltage, current and

power (input); and Battery voltage, current and power (output). 4. When connecting the KM2 converter screw version note that in the KMi the ground

connection is always to the outside of the PCB, while in the KM2 on the inside, as detailed in Fig. 2.

5. The KMi can be disabled by removing the jumper on the side of the PCB from across the two middle positions. Set it to either other position. See Fig. 3.

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KMi: Interface Display for the KM2

KMi-series Datasheet © 2015 Thermoelectric Conversion Systems Limited Issue B – March 2016

Fig. 2: Connection of the KMi interface board to the KM2 converter screw version.

Fig. 3: Enable jumper location.

Jumper to disable the KMi

interface board

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KMi: Interface Display for the KM2

KMi-series Datasheet © 2015 Thermoelectric Conversion Systems Limited Issue B – March 2016

Product Drawings

Fig. 4: Mechanical drawing of the KMi board.

Thermoelectric Conversion Systems Limited (TCS) does not assume any responsibility for use of any circuit described, no circuit patent licenses are implied and TCS reserves the right at any time without notice to change said circuitry and specifications.

This TCS product is not authorised for use as critical component in life support devices.

Thermoelectric Conversion Systems Limited - www.Teconversion.com