原标题：IR IRS2530D三级调光CFL镇流器方案

　　IR公司的IRS2530D是全特性的调光镇流器控制和半桥驱动器,可以实现简单的单片高性能调光镇流器解决方案.它采用闭环灯丝电流调光控制,内部具有非ZVS保护和峰值因子保护,预热时间可编程.本文主要介绍了IRS2530D主要特性和镇流器系统的主要特性, IRS2530D方框图,以及采用IRS2530D的IRPLCFL8U电路图和材料清单(BOM).

　　IRS2530D takes full advantage of IR’s patented ballast and high-voltage technologies to realize a simple, high-performance dimming ballast solution. A single high-voltage pin senses the half-bridge current and voltage to perform necessary ballast protection functions. The DC dim input voltage reference and the AC lamp current feedback have been coupled together allowing a single pin to be used for dimming. Combining these high-voltage control algorithms together with a simple dimming method in a single 8-pin IC results in a large reduction in component count, an increase in manufacturability and reliability, a reduced design cycle time, while maintaining high dimming ballast system performance

　　IRS2530D主要特性:

　　Dimming ballast control plus half-bridge driver

　　Closed-loop lamp current dimming control

　　Internal non-ZVS protection

　　Internal crest factor protection

　　Programmable preheat time

　　Fixed dead-time (2.0μs typ.)

　　Lamp insert auto-restart

　　Internal bootstrap MOSFET

　　Internal 15.6V zener clamp diode on Vcc

　　Micropower startup (250μA)

　　Latch immunity and ESD protection

　　镇流器系统特性:

　　Single chip dimming solution

　　Simple lamp current dimming control method

　　Single lamp current sensing resistor required

　　No half-bridge current-sensing resistor required

　　No external protection circuits required (fully internal)

　　Flash-free lamp start at all dimming levels

　　Large reduction in component count

　　Easy to use for fast design cycle time

　　Increased manufacturability and reliability

　　典型应用:

　　Linear dimming ballast (down to 10%)

　　3-way dimming ballast

　　Multi-level switch dimming ballast

　　图1.IRS2530D方框图

　　图2.IRS2530D典型应用连接图

　　采用IES2530D的简化三级调光CFL镇流器主要特性:

　　Simplified Three Level Dimming CFL Fluorescent Ballast using the IRS2530D

　　Features

　　Drives 1 x 32W Spiral CFL Lamp

　　Input Voltage: 120Vac

　　High Frequency Operation

　　Lamp Filament Preheating

　　Lamp Fault Protection with Auto-Restart

　　Low AC Line/Brownout Protection

　　IRS2530D DIM8TM HVIC Ballast Controller

　　图3. 三级调光CFL镇流器外形图

　　图4.三级调光灯丝系统

　　图5.采用IR2156的IRRLCFL4电路图

　　图6.采用IRS2530D的IRPLCFL8U电路图

　　The IRS2530D design utilizes a voltage doubler at the front end in all modes of operation

　　giving a fixed DC bus voltage approximately 300V. By correctly selecting value of the

　　snubber capacitor it is not difficult to achieve soft switching in all modes of operation.

　　The front end of the IRPLCFL8U ballast circuit shows the neutral line input (i.e. the one

　　that is always connected) connected to the center point of the DC bus storage capacitors

　　C3 and C4. Live inputs L1 and L2 are connected to two completely separate voltage

　　doubler diode pairs which are connected to the DC bus. These four diodes are all

　　contained within the bridge BR1 (This is shown as D1, D2, D3 and D4 in the schematic of

　　Fig 6). If live input L1 is connected to the line, a 60Hz sinusoidal AC voltage will be present at the point where the anode of D1 joins the cathode of D3. This voltage will swing

　　between the 300V DC bus voltage and the 0V COM point of the circuit. If live input L1 is

　　not connected to the line this point will be floating with only residual voltage present. The

　　same applies with live input L2 at the point where the anode of D2 meets the cathode of

　　D4. These two points are fed via resistors R5 and R6 to the parallel combination of R7 and

　　C5, which are connected to 0V COM. The value of C5 is high enough to ensure that the

　　amount of ripple that is present at the junction of C5 and RDIM will be negligible so a DC

　　voltage will effectively appear there. This sets the reference voltage level for the dimming

　　feedback loop.

　　As a result this dimming control voltage will change depending on whether live input L1 is

　　connected only, live input L2 is connected only or both are connected, which depends on

　　the three way dimming rotary switch position. The values of R5 and R6 will be chosen so

　　that this voltage is substantially different if either live input L1 of live input L2 are

　　connected alone and these values are selected to set the desired low and mid light levels.

　　In this application R5 can be selected to give the correct reference voltage to provide 50%

　　light output as perceived by the human eye, which occurs at a point somewhat lower than

　　50% ballast power and R6 can be chosen for 75% which is at about 50% of the nominal

　　total ballast power at full light output.

　　The design problem overcome here is that the dimming control voltage obtained through

　　R5 and R6, where the values have been selected to provide minimum and medium light

　　outputs, is not sufficiently high to provide maximum light output when both live inputs are

　　connected. This being the case it was necessary to add the two pull up transistors Q1 and

　　Q2. When both inputs L1 and L2 are connected, i.e. when the rotary switch is in the fully

　　on position, the voltage at RDIM will be pulled high enough to ensure that the ballast

　　operates at maximum output since the transistors Q1 and Q2 will both be switched on in

　　this case.

　　Q1 and Q2 are small signal NPN devices, however they need to be rated to 300V VCEO

　　to prevent any conduction if either one is switched off. The zener diode DZ1 had been

　　added to ensure that Q1 and Q2 can fully switch off. This is because even when not

　　connected to the line some voltage appears at the bases of these devices. Since Q1 and

　　Q2 are configured as emitter followers the base voltage must exceed the breakdown

　　voltage of DZ1 (68V) in order to switch on, which can only occur when the corresponding

　　line input is connected through the rotary switch.

　　IRPLCFL8U 材料清单(BOM):