Research and development of cost-effective HID electronic ballast

More than a decade ago, at the request of a friend, I started to develop HID electronic ballasts. At that time, I knew nothing about the characteristics of HID lamps. When I used an ordinary fluorescent lamp electronic ballast to light up an HID lamp easily, it seemed that success was in the near future. When the lamp power was close to the rated power, the lamp flickered and an acoustic resonance occurred. At that time, I didn't even know it was an acoustic resonance..., and then began a long research and development process... Since the development of HID electronic ballasts was not my official job, I could basically only do it in my spare time. It has been going on for 6 years, "off and on" because I encountered difficulties and "on" because I thought of a new idea. My goal was high cost performance. At that time, there were very few dedicated ICs for HID electronic ballasts, and the price was extremely high. The function of the IC also stipulated the circuit topology, so the cost of the whole machine was very high, and it was impossible to be a cost-effective electronic ballast. I had to find another way out.

After countless thoughts and failures, the cost-effective HID electronic ballast was finally developed around 2000. In order to add color to the "Second Original Post Competition of Power Supply Network", this research and development result is now publicly released.

Main components of L-class 250W high pressure sodium lamp electronic ballast:

MOSFET : IR FP450 3pcs

IC: MC34262, TL494, LM324, one each

Main inductor components: EC35 (transformer or inductor) 3 pieces; EE16 (transformer) 2 pieces

1 6A rectifier bridge;

MUR460 1 piece.

Electrolytic capacitor : 220UF/250V 2pcs.

Main technical indicators of L-class 250W high pressure sodium lamp electronic ballast:

Input voltage : AC220V±20%

Power factor: ≥0.99

Efficiency:＞91%

Lamp Current Crest factor: about 1.4

Lamp voltage: 100V±20V

Output power: Constant power, measured (lamp voltage 90-110V) output power fluctuation <5%

Lamp power (lumen 100%): about 225W-230W

Protection: lamp short circuit, lamp open circuit, overheating.

Due to the limitations of test conditions, the above data is for reference only.

This design only made a few samples and was not put into production.

The 250W high-pressure sodium lamp electronic ballast passed the most severe destructive high-temperature test: high-temperature oven at 125℃, continuous operation for 6 hours. When the electronic ballast was taken out of the oven, the terminal was deformed and the outer skin of the electrolytic capacitor was cracked.

In order for everyone to see clearly, the schematic diagram is divided into 7 pictures.

I will first raise some questions and then gradually explain the design ideas.

This design idea is also applicable to metal halide lamps.

Figure 1: L-class 250W high pressure sodium lamp Electronic Ballast block diagram

Figure 2: Input filter and rectifier circuit

Figure 3: PFC

Figure 4: Auxiliary Power Supply

Figure 5: Inverter main circuit

Figure 6: Control circuit

Figure 7: MOS tube drive circuit

Figure 8: Temperature protection, op amp power supply (9V), voltage reference circuit