Digital Power Factor Correction Control IC with Accurate AC Power Metering - ADP1047

When designing AC/DC, not only a digitally controlled full-bridge control IC-ADP1043 is required, but also its power factor correction part also needs a digitally controlled device. ADP1047 is such a new product, which can not only complete power factor correction, but also accurately measure AC power and control the ability to resist impact when the power is turned on.

The digital PFC function is based on the PFC topology of the traditional boost mode, combining multiple output voltage feedbacks to provide the best harmonic correction and good PF value. All signal controls enter the field of digital control and provide the greatest flexibility-all key parameters can be reported and given through the PM bus interface, so that users can obtain the best performance, the most efficient power factor correction circuit, and can greatly reduce the design time.

Digital PFC control is particularly suitable for intelligent power management systems and is easy to measure, improving the efficiency of end-user systems through intelligent power management systems. The power consumption at light load is further reduced by adjusting the frequency, and the output voltage can be reduced to low-voltage loads.

1 Main features

ADP1047 can provide accurate measurement of rms input voltage, current and power, and can report to the secondary side of the power supply through the PM bus. ADP1047 has enhanced integration and functions to cope with surge impact, which can greatly reduce the number of peripheral components and easily achieve optimized design.

The goal of device digitization is also for higher reliability and open circuit for a variety of power supply applications. The circuit has rugged protection functions, including overvoltage protection, overcurrent protection, ground continuity measurement, AC detection, internal overheat protection, and external temperature reporting.

ADP1047 has an internal 8KB EEPROM to store the regulator and allows independent control without a microcontroller, through an easy-to-use GUI adjustment. ADP1047 is powered by 3.3V power supply, 24P IN external pins, and the operating environment is -40～+85℃.

2 Pin Function

The pin arrangement of ADP1047 is shown in Figure 1. The following is an introduction to the pins of ADP1047.

1PIN: AGND. Analog ground, directly connected to DGND, where the analog voltage is sent to the analog-to-digital converter ADC.
2PIN: VAC. Input line voltage detection, this signal refers to PGND.
3PIN: VFB. Feedback voltage detection terminal, sampled from the PFC output voltage and sent here, referenced to the power ground, used as an analog voltage to the analog-to-digital converter ADC.
4PIN: OVP. Overvoltage protection, this signal refers to PGND and is used as an OVP function.
5PIN: PGND. Power ground, connected to the input and output power rails.
6PIN: ILIM. Current limit terminal, peak current limit, referenced to PGND.
7PIN: NC. Empty pin.
8PIN: CS-. Current detection negative input terminal, used for current measurement, metering and protection.
9PIN: CS+. Current detection positive input terminal, used for current measurement, metering and protection.
10PIN: DGND. Digital ground, ensure low impedance connection with analog ground AGND.
11PIN: PSON. Power enable signal, this signal is used to enable or disable the PFC controller.
12PIN: VCORE. 2.5V output regulator, external 0.1μF capacitor bypass to DGND.
13PIN: PWM. Pulse width modulation output for PFC.
14PIN: PWM2. Auxiliary PWM, this signal refers to DGND.
15PIN: AC-OK. Open drain output, used for signal flag output, refer to DGND.
16PIN: PGOOD. Open drain output, used for signal flag output, refer to DGND.
17PIN: INRUSH. Inrush control signal, used for external inrush control driver.
18PIN: SYNC. Controller external synchronization terminal, this terminal allows the PFC controller connected in parallel to be desynchronized to reduce interference.
19PIN: SCL. I2C serial clock input, refer to DGND.
20PIN: SDA. I2C signal data input and output terminal, refer to DGND.
21PIN: ADD. Address selection input, connect a resistor from this end to AGND.
22PIN: RTD. Temperature signal input, place a thermistor here and connect it to AGND.
23PIN: RES. Internal voltage reference, connect a 50kΩ resistor to NAGND.
24PIN: VDD. IC power supply, from 3.0 to 3.6V. External capacitor bypasses NAGND.

3 Working principle and application

The internal functional block diagram of ADP1047 is shown in Figure 2. ADP1047 is a digital PFC controller that performs AC power factor correction. It has many traditional PFC features: it uses BOOST topology, can generate detection voltage and detection current, and can generate adjustable PWM output.

ADP1047 is designed with rugged protection functions, including overvoltage protection (OVP), overcurrent protection (OCP), undervoltage protection (UVP), ground continuity measurement, AC detection, internal overtemperature protection and external temperature reporting, so it can be used in a variety of power supplies.
These functions of ADP1047 can be adjusted through the I2C bus interface, and this bus interface is also used to calibrate various power supply parameters, including input voltage, input current, input power, fault mode, etc.

The control loop of ADP1047 is controlled by a digital control system, and the filtering characteristics can be easily adjusted. The data established in the EEPROM is used to store the adjustment value, and the reliability is guaranteed by the check sum and redundancy circuit. When a system fault occurs, the EEPROM can capture the first fault condition to improve the reliability of the entire system, thereby greatly reducing the fault analysis time.

The ADP1047 operating software is CUI, which can provide all the operating software.
Figure 3 shows a typical PFC circuit of digitally controlled power factor correction composed of ADP1047.