LED driver IC product design, why is the LYTSwitch-6 series so eye-catching?

To sum up, the challenge comes from the following aspects:

Lower standby power consumption: Need to meet increasingly stringent energy efficiency standards, while also ensuring that the auxiliary power supply has output when the main output is unloaded, providing stable and reliable power supply for the IoT wireless microprocessor controller module.

Driving different types of loads: Sometimes a constant current output characteristic of a single string is required, and sometimes the required constant voltage output characteristics of multiple strings are required in parallel.

Output distortion as small as possible: Under dynamic load, keep the output voltage stable to prevent the brightness of each string from interfering with each other.

Support for dimming: Requires support for existing analog and PWM dimming functions.

It can be seen that the LED driver IC selected by intelligent lighting must be an "all-round" player that meets various needs.

[ Figure 1, power supply challenges facing smart lighting]

To this end, Power Integrations (hereinafter referred to as PI) recently introduced the LYTSwitch-6 series of safely isolated LED driver ICs. According to the information provided by PI, this product can be said to be a hit smart lighting power supply. The "pain point" of the drive design:

First, the LYTSwitch-6 is up to 94% efficient and has a standby power as low as 15 mW, making it easy to meet North American DOE-6 and ENERGY STAR requirements.

Second, LYTSwitch-6 supports both constant voltage (CV) and constant current (CC) outputs. One solution supports different design applications with constant voltage and constant current accuracy of ±3%.

Third, the LYTSwitch-6 fast response control reduces output ripple, allowing for smaller output capacitors in the system design; optimized transient response characteristics and excellent load regulation, making it suitable for a wide variety of applications. Load scenarios, such as RGB tri-color illumination where each load can vary.

In addition, LYTSwitch-6 supports both analog and PWM dimming, making the product more versatile and convenient.

[Figure 2, LYTSwitch-6 product line in InSOP-24C package]

The eye-catching performance of the LYTSwitch-6 series, of course, is indispensable to the various "black technology" behind it. Among them is a well-known figure - PI's unique FluxLink magnetic coupling technology. Because of the combination of the accuracy of the secondary side control scheme and the simplicity of the primary side control architecture, it is possible to isolate and complete the first time without optocoupler. Communication between the levels, so it has been applied in many of PI's flagship products. The direct effect of using FluxLink technology in LYTSwitch-6 is to improve the precise control of the output voltage and current. In addition, since the two controllers are integrated in a single IC, the synchronous rectification switching timing can be precisely controlled, resulting in higher efficiency and longer drive life.

[Figure 3, PI's original FluxLink magnetic induction coupling technology can achieve more accurate constant current and constant voltage control, and meet safety regulations]

In terms of improving efficiency, LYTSwitch-6 uses quasi-resonant switching mode in addition to synchronous rectification. With the conversion of different working states of the power supply, the quasi-resonant switching mode will automatically intervene, making the efficiency of the power conversion stage of the flyback topology available. More than 94%, so you can provide up to 65W of high power output without using a heat sink. In Figure 4, the standby power consumption of an LED power supply capable of providing 45W/80V output using the LYT6068C in the LYTSwitch-6 series is shown. It can be seen that the power consumption is much lower than the power consumption over a wide input voltage range. Standard requirements.

[Figure 4, LYTSwitch-6 standby power consumption can easily meet the energy consumption standard requirements]

Let me talk about the LYTSwitch-6 "super" stable load adjustment capability. The LYTSwitch-6 uses an advanced variable frequency on-off control that makes the control loop extremely responsive, eliminating the need for an op amp or optocoupler in the loop, so the control loop does not have any phase shift. Compared to the traditional on/off mode of operation (Figure 5, top left) or PWM mode of operation (Figure 5, bottom left), the output ripple of LYTSwitch-6 (Figure 5, right) with this unique control scheme can be greatly Lowering, this greatly improves the flicker that the user cares about in lighting applications.

[Figure 5, LYTSwitch-6 can achieve lower output ripple than traditional loop control schemes]

Efficient loop control also provides better dynamic response, allowing LYTSwitch-6 to avoid drastic changes in output voltage during sudden load spikes. A typical power supply will have a significant undershoot or overshoot of the output voltage when the load changes greatly. As can be seen from Figure 6, when the load is 0-100% transitioned in the power supply based on the LYTSwitch-6 design, Almost no change in output voltage is felt. This is especially important for smart lighting applications with multiple strings, which do not affect the brightness of other outputs due to drastic changes in the brightness of a string of beads.

[Figure 6, excellent dynamic response characteristics of LYTSwitch-6]

Hubie Notohamiprodjo, Director of LED Lighting Product Marketing at PI, commented on LYTSwitch-6: The LYTSwitch-6 IC is suitable for smart lighting applications with multiple outputs. By eliminating the heat sink and optocoupler and reducing the size of the output capacitor by 30%, the overall component count and system size are also greatly reduced.

In the increasingly fierce and increasingly competitive smart lighting market, such "all-powerful" products that know how to save money will surely be favored by more and more developers.