PAC1720 Click

How does it work?

PAC1720 Click as its foundation uses the PAC1720, a dual bidirectional high-side current-sensing device with precision voltage measurement capabilities from Microchip Technology. It measures the voltage developed across external sense resistors to represent the high-side current of a battery or voltage regulator, then digitizes it with a variable resolution Sigma-Delta ADC and transmits it over the I2C protocol. The PAC1720 also measures the SENSE+ pin voltages and calculates average power over the integration period.

The PAC1720 has three states of operation: Active, Standby, and One-Shot Mode. In Active mode, the PAC1720 initiates conversion cycles for the programmed conversion rate. The Standby mode represents the lowest power state, where there are no conversion cycles. The majority of circuitry is powered-down to reduce supply current to a minimum. While the device is in the Standby state, the host can initiate a conversion cycle on-demand using One-Shot mode. After the conversion cycle is complete, the device will return to the Standby state.

PAC1720 Click communicates with MCU using the standard I2C 2-Wire interface to read data and configure settings, supporting operation with a clock frequency up to 400kHz. Besides, it also allows the choice of its I2C slave address by positioning the SMD resistor of appropriate value labeled as R2, giving the user the ability to select one of eight possible slave addresses.

The current range allows for significant variations in measured current with high accuracy and the low voltage drop across the resistor. The PAC1720 has programmable high and low limits for current sense and bus voltage with a maskable alert signal labeled as INT, routed to the RST pin of the mikroBUS™ socket, to the host when an out-of-limit measurement occurs.

This Click board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the I2C communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.

Specifications

Pinout diagram

This table shows how the pinout on PAC1720 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	NC
	NC	2	RST	INT	15	INT	Interrupt
	NC	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	SCL	I2C Clock
	NC	6	MOSI	SDA	11	SDA	I2C Data
Power Supply	3.3V	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

PAC1720 Click electrical specifications

Software Support

We provide a library for the PAC1720 Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for PAC1720 Click driver.

Key functions

• pac1720_set_vsource_config This function sets the Voltage Source configuration (sample time and average samples) for the selected channel.

• pac1720_set_vsense_config This function sets the Voltage Sense configuration (sample time, average samples, and sampling range) for the selected channel.

• pac1720_get_measurements This function reads voltage, current, and power from the selected channel.

Example Description

This example demonstrates the use of PAC1720 Click board™ by reading the voltage, current, and power from both available channels.

 void application_task ( void ) 
 { 
     float voltage = 0, current = 0, power = 0; 

     if ( PAC1720_OK == pac1720_get_measurements ( &pac1720, PAC1720_CHANNEL_1, &voltage, &current, &power ) ) 
     { 
         log_printf( &logger, " Channel 1:rn" ); 
         log_printf( &logger, " U: %.3fV, I: %.3fA, P: %.3fWrn", voltage, current, power ); 
     } 

     if ( PAC1720_OK == pac1720_get_measurements ( &pac1720, PAC1720_CHANNEL_2, &voltage, &current, &power ) ) 
     { 
         log_printf( &logger, " Channel 2:rn" ); 
         log_printf( &logger, " U: %.3fV, I: %.3fA, P: %.3fWrnn", voltage, current, power  ); 
     } 

     Delay_ms( 1000 ); 
 }

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.PAC1720

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MikroElektronika compilers.

mikroSDK

This Click board™ is supported with mikroSDK – MikroElektronika Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.