Introduction of Infineon’s innovative intelligent digital LED driver

LED lighting has been popularized in the entire lighting application. With the development of smart cities and smart street lights, LED driving power is also developing towards intelligence and digitization. As a leading supplier of smart LED lighting, Infineon looks at the problem from a system-level perspective and provides customers with excellent digital products and solutions. While providing high-performance products and system solutions, it greatly reduces the The pressure of customer inventory and the cycle of new product introduction expand the flexibility of R&D design. Infineon lighting driver IC with its rich product types, a wide range of topology combinations, with industry-leading power Transistor CoolM

LED lighting has been popularized in the entire lighting application. With the development of smart cities and smart street lights, LED driving power is also developing towards intelligence and digitization. As a leading supplier of smart LED lighting, Infineon looks at the problem from a system-level perspective and provides customers with excellent digital products and solutions. While providing high-performance products and system solutions, it greatly reduces the The pressure of customer inventory and the cycle of new product introduction expand the flexibility of R&D design. Infineon’s lighting driver IC, with its rich product types, extensive topology combinations, and industry-leading power Transistor CoolMOS technology, fully meets the needs of semiconductor device selection for LED driver power design.

Infineon’s digital control solution is based ON its own digital core CPU, combined with powerful power Semiconductor manufacturing technology, and organically integrates the two, innovating the industry’s leading digital LED driver IC technology, and has already mass-produced 3 products. , XDPL8105, XDPL8220, ILD2111. XDPL8221 is a new member of Infineon’s series of digital intelligent LED driver ICs. It integrates PFC and flyback controller. It is packaged in SO16 narrow body. It has three output working states of constant current, constant voltage and limited power, and independent dimming interface. and communication interface, extremely low THD and standby power consumption, making it highly competitive.

1.Overview of Infineon Digital Controllers

The concept of Infineon’s digital controller is shown in Figure 1. The core embedded CPU is Infineon’s own digital core, and the power conversion control reduces the load of the CPU and improves the system efficiency. Peripheral integrated ADC converter and power high Voltage start-up unit and driver. Complete protection functions are also integrated.

Introduction of Infineon’s innovative intelligent digital LED driver

Figure 1 Infineon digital controller

2. XDPL8221 System Overview

The typical system principle of XDPL8221 is shown in Figure 2. XDPL8221 highly integrates critical mode PFC and primary-side control quasi-resonant flyback controller, which greatly reduces the number of system components. The two-stage scheme reduces output ripple, reduces the design margin requirements of a single stage, and further reduces costs.

XDPL8221 integrates THD optimization algorithm, which makes the system have high PF value and low THD value. The unique constant voltage, constant current, and power-limited control modes can be switched freely, providing extremely high load flexibility, and system designers and developers can maximize the use of system hardware capabilities.

The in-chip OTP unit stores system parameters such as output current, output voltage, maximum output power, protection mode, and more. Parameters can be reconfigured in the R&D stage or on the mass production line, which enables users to generate different models without changing the hardware parameters, so as to achieve the real purpose of multiple models on one platform.

The demand for low standby power consumption is increasing in lighting applications, and the standby requirements are getting lower and lower. The standby power consumption of XDPL8221 as low as 100mW has set a new benchmark in the industry.

In addition, internal and external adaptive over-temperature protection functions and other protection functions guard the safety and reliability of the system.

Introduction of Infineon’s innovative intelligent digital LED driver

Figure 2 XDPL8221 typical system

The following chapters will mainly introduce the principle of XDPL8221 precise primary control, PF/THD optimization algorithm, dimming performance, protection function, and unique real-time communication function.

2.1 XDPL8221 primary control principle and accuracy

The typical waveform diagram of XDPL8221 primary side control is shown in Figure 3. The system calculates the secondary current and overcurrent protection by detecting the peak current of the primary side of the flyback transformer. The secondary voltage is calculated by detecting the reflected voltage of the auxiliary winding. At the end of the demagnetization time, the output voltage value can be calculated by detecting the voltage value of the ZCD pin. On the basis of known output voltage and current, the power limit control is realized through software algorithm.

Introduction of Infineon’s innovative intelligent digital LED driver

Figure 3 XDPL8221 primary control principle

Figure 4 shows the output characteristic curve of XDPL8221. In the constant voltage section, the power supply works in the constant voltage region, and the output current needs to be lower than a certain value according to the load state. In the constant current section, the power supply works at the constant current point, and the output voltage must be lower than a certain value to ensure that the output power of the entire system is within the control range. In the limited power section, the product of voltage and current must be less than or equal to the set maximum output power. In the limited power mode, the accuracy of the limited power is within 2%. Power-limited mode applications are more suitable for driving COB lamp beads.

Introduction of Infineon’s innovative intelligent digital LED driver

Figure 4 XDPL8221 output characteristic curve

2.2 XDPL8221 system input PF value and THD value

The XDPL8221 integrates the THD optimization function, which makes the THD maintain excellent THD performance over the entire input voltage range and a wide range of output power.

Introduction of Infineon’s innovative intelligent digital LED driver

Figure 5 THD optimization algorithm and 50W demoboard THD test results

Figure 5 shows the measured THD curve on the right. It can be seen from the curve that under the full voltage input state, in the range of 30% load to 100% load, the THD can be lower than 12%, and it can also meet the requirements of EN61000-3-2 standard.

2.3. XDPL8221 Dimming Performance

The XDPL8221 integrates four dimming curves, as shown in Figure 6, which are mainly divided into Linear dimming and curve dimming modes. Each mode can also support forward dimming or reverse dimming. The minimum PWM DUTY corresponding to the minimum dimming current can be set in the software interface, and the maximum PWM DUTY corresponding to the maximum dimming current can also be set in the software. XDPL8221 supports dimming depth less than 1%, supports dimming function, and the hysteresis of dimming setting can be set in software.

Introduction of Infineon’s innovative intelligent digital LED driver

Figure 6 XDPL8221 dimming curve

Figure 7 is the measured dimming curve, and the dimming depth is less than 1%. And with different loads, the dimming curves tend to be consistent.

Introduction of Infineon’s innovative intelligent digital LED driver

Figure 7 XDPL8221 dimming curve test

2.4 Protection function

XDPL8221 has complete protection functions, which can realize AC input voltage overvoltage and undervoltage protection, output voltage overvoltage and undervoltage protection, and output current average current and peak current overcurrent protection; and has a dedicated pin for external temperature protection, used for Do systematic over-temperature protection. And there is also an over-temperature protection mechanism inside the IC body to protect the IC itself.

Introduction of Infineon’s innovative intelligent digital LED driver

Figure 8 Adaptive temperature protection

Figure 8 shows the XDPL8221 intelligent temperature protection curve. During over-temperature protection, the system output current will gradually decrease until the set minimum current. At this time, if the temperature protection is released, the output current will gradually increase to the maximum operating current; The temperature protection always exists but does not exceed the maximum over-temperature point, and the system will always work at the minimum output current state. This mode of over-temperature protection greatly ensures the lighting time of the lamp.

2.5 Real-time communication function

XDPL8221 has real-time communication function. Through the UART pin of IC, it can realize real-time control of output current or dimming brightness and switch control of the whole lamp, and can also read the working status, output status and abnormal protection status of the system in real time. The communication adopts the half-duplex UART protocol, and realizes the communication function with 8-bit data. This real-time communication function can be used for smart street lights or smart indoor and outdoor lighting applications, which is convenient for centralized control, and intelligently reports the working status of each light or the abnormal protection that has occurred, which is convenient for later maintenance.

Introduction of Infineon’s innovative intelligent digital LED driver

Figure 9 Real-time communication software interface

From the real-time communication software in Figure 9, it can be seen that the working status, input voltage, output voltage and current and dimming status of the IC can be known in real time, and the software can also be used to implement switching actions or set the dimming level.

3.Communication and parameter configuration tools

The Infineon digital control IC has a communication interface, and can use the provided interface board to connect the target board with the PC. Users can modify the parameters at any time according to actual needs, which greatly improves the flexibility of system design and shortens the system. Development time.

A typical parameter configuration system and interface are shown in Figure 10.

Introduction of Infineon’s innovative intelligent digital LED driver

Figure 10 Typical settings and configuration interface of parameter configuration system

In the parameter configuration software, it is not necessary for the customer R&D engineer to know software programming, but only need to know the hardware design to use this configuration software well. In the configuration software, the engineer needs to input the peripheral hardware parameter information of the IC and the system input and output specification parameters, and then write the configured parameters into the IC to start the test.

4 Conclusion

This article describes an overview of Infineon’s digital control ICs and an overview of the driver chip XDPL8221 developed for lighting application requirements. At present, XDPL8221 can meet the requirements of most intelligent lighting control chips.

The Links:   A056DN01-V5 SKIIP35NAB126V1