Evaluating the LT8722

Supported Evaluation Boards

• DC3145A

Overview

Demonstration circuit 3145A demonstrates a high efficiency thermoelectric cooler driver and features the LT8722 monolithic driver.

The input voltage range of the DC3145A is from 3.1V to 15V and the output is a SPI programmable differential voltage output. The maximum output current is 4A. The switching frequency SPI programmable from 500kHz to 3MHz.

The LT8722 is controlled through an SPI interface and therefore the demonstration circuit is also setup to interface through SPI.

Full performance details are provided in the LT8722 data sheet, which should be consulted in conjunction with user guide.

Hadrware Specifications

Power Supply Requirments

For this specific project an external power supply is used to provide a 3.1V to 15V input voltage for the DC3145A evaluation board. The board also needs a 2.7V to 5.5V supply to power the serial interface.

Board Connector and Jumper Settings

The (JP1) jumper has two positions: LIN and MAN. Connect the jumper to the LIN position to allow the MCU to control the state of the SWEN pin via GPIO.

The (JP3) jumper has two positions: ENABLE and LIN. Connect the jumper to the LIN position to allow the MCU to control the state of the EN pin via GPIO.

Pin Description

Please see the following table for the pin assignments for the interface connector (JP2).

JP2:

Pin	Name	Description
1	NC	No Connection
2	L-VSPI	Connect to VDDIO supply (2.7V to 5.5V)
3	GND	Connect to Ground
4	SCK	Connect to SPI Clock (SCK)
5	MISO	Connect to SPI Master In Slave Out (MISO)
6	#CS	Connect to SPI Chip Select (CS)
7	MOSI	Connect to SPI Master Out Slave In (MOSI)
8	GND	Connect to Ground
9	NC	No Connection
10	NC	No Connection
11	LIN_ENA	Connect to GPIO pin (ENABLE)
12	GND	Connect to Ground
13	GND	Connect to Ground
14	LIN_SWEN	Connect to GPIO pin (SWEN)

No-OS Build Setup

Please see: https://wiki.analog.com/resources/no-os/build

No-OS Supported Examples

The initialization data used in the examples is taken out from: Project Common Data Path

The macros used in Common Data are defined in platform specific files found in: Project Platform Configuration Path

Basic example

This is a simple example that initializes the LT8722, perform the start-up sequence and configure the output voltage.

In order to build the basic example make sure you have the following configuration in the Makefile

# Select the example you want to enable by choosing y for enabling and n for disabling
BASIC_EXAMPLE = y
IIO_EXAMPLE = n

IIO example

This project is actually a IIOD demo for DC3145A evaluation board. The project launches a IIOD server on the board so that the user may connect to it via an IIO client.

Using IIO-Oscilloscope, the user can configure the device.

If you are not familiar with ADI IIO Application, please take a look at: IIO No-OS

If you are not familiar with ADI IIO-Oscilloscope Client, please take a look at: IIO Oscilloscope

The No-OS IIO Application together with the No-OS IIO LT8722 driver take care of all the back-end logic needed to setup the IIO server.

This example initializes the IIO device and calls the IIO app as shown in: IIO Example

In order to build the IIO project make sure you have the following configuration in the Makefile

# Select the example you want to enable by choosing y for enabling and n for disabling
BASIC_EXAMPLE = n
IIO__EXAMPLE = y

No-OS Supported Platforms

Maxim Platform

Used hardware

• DC3145A evaluation board

• MAX32666FTHR

Connections:

DC3145A (JP2) Pin Number	Function	MAX32666FTHR Pin
2	VDDIO (2.7V to 5.5V)	3V3
4	SPI Clock (SCK)	AIN3 (SPI1_SCK)
5	SPI Master In Slave Out (MISO)	AIN2 (SPI1_MISO)
6	SPI Chip Select (CS)	AIN0 (SPI1_SS0)
7	SPI Master Out Slave In (MOSI)	AIN1 (SPI1_MOSI)
11	GPIO (EN Pin)	AIN4 (P0_20)
12	Ground (GND)	GND
14	GPIO (SWEN Pin)	AIN5 (P0_21)

Build Command

# to delete current build
make PLATFORM=maxim TARGET=max32665 reset
# to build the project and flash the code
make PLATFORM=maxim TARGET=max32665 run