S6510 Ballast Controller

Transcription

1 Semiconductor S6510 Ballast Controller Description The device provides simple and performance electronics ballast control function for the half bridge L/C resonant inverter. This device is optimized for electronics ballast requiring a minimum board area, reduced component count and low power dissipation. Internal soft start circuitry eliminates the need for an external soft start PTC resistor. The initial soft start frequency and soft start time can be easily adjusted depending on the types of lamp. Prevent burning out of switches in no lamp condition. Internal 18V regulator clamps Vcc line of supply voltage for eliminating an external zener diode. Features No lamp protection Low Start up & Operating Current Internal Soft Start Flexible Soft Start Frequency Trimmed 1.5% internal Reference Under Voltage Lock Out with Hysteresis High Current Totem Pole Gate Drive Internal Block Diagram Cs 1 ics Current Multiplier Vref 2V Vref Internal bias Under Voltage Lock Out uvlo 8 18V Vcc Ct 2 Oscillator ict ic is ik = ir / 2 Vth(st) Regulator 7 OUT1 8ict S R Q Q Output Driver 1 Rs 3 2k Vref Buffer ir Current Mirror ik Frequency Divider Output Driver 2 6 OUT2 Ldet 4 Vz 100k 50k 10pF Vref No Lamp Detector Shut Down Signal to OSC Delay Timer ir = Vref / Rs ik = ir / 2 is = ik x ( Vref Vcs) / Vref 5 GND Lighting Application With Gate Driver IC S

2 Startup Circuit Start up current is supplied to the IC through the start up resistor (Rst). In order to reduce the power dissipation in Rst, the Rst is connected to the full wave rectified output voltage. The following equation can be used to calculate the size of Rst Rst < Vin(ac) < 2 Vth(st),max Ist,max P RST = (Vir(ac_max) * 2 Vcc) 2 Rst 0.5W 260K Rst 440K The size of start up capacitor (Cst) is normally decided in terms of the start up time and operating current build up time with auxiliary operating current source. The turn off snubber capacitor (Cq2) and two diodes (D1, D2) constitute the auxiliary operating current source for the IC. The charging current through the Cq2 flows into the IC and also charges the startup capacitor. If the size of Cq2 is increased, the VCC voltage of the Cst is also increased. Figure 1. Start up circuit Rectifier Output Q1 Q2 Cq2 Rst To Vcc (Pin 8) D2 D1 Cst Oscillator The gate drive output frequency is as half as that of the triangular waveform in timing capacitor (Ct) at pin #2. In normal operating mode, the timing capacitor charging current is 50 μa. The discharging current is seven times of the charging current (7 50 μa ). The charging period of the timing capacitor is the on duty of the gate drive. The discharging period is the off duty of the gate drive. The rising slope and falling slope of the triangular waveform are as following. Rising slope: dv / dt = i / C = 50 μa / Ct Falling slope: dv / dt = i / C = 7 50 μa / Ct Lighting Application With Gate Driver IC S

3 Figure 2. Oscillator sawtooth & Output gate drive waveform Vct (pin #2) 2.0V Vout (pin #6,7) 1.0V 7V 0V Charging Period ( Tch) Discharging Period ( Tdis) For example, when the timing capacitor is 470pF, Tch = 9.4 μs, Tdis = μs As a result, the switching frequency is as following Ts = 2 ( Tch Tdis) = μs fsw = 1 / TS 45KHz Soft Start The switching frequency is linearly decreasing from the preheating frequency to the normal switching frequency. In S6510, the initial preheating frequency can be adjusted depending on the types of the lamps used. During the preheating mode, a sixth of the soft start current (I S ) which flows through the soft start resistor (R S ) at pin #3 is added to the normal timing capacitor charging current (50 μa ). The rising and falling slope of the triangular waveform are increased due to this added current. Soft start current (I S ) = 2V / R S Rising slope: dv / dt = i / C = (50 μa I S / 6) / Ct Falling slope: dv / dt = i / C = 7 (50 μa IS / 6) / Ct So, once the value of RS and Ct are known, the preheating frequency can be calculated straightforward by using the following equation. The dead time ratio during preheating mode is maintained to be constant as well as in normal mode. (on duty: dead time = 7:1 ) fsw(pre ) = (0.33/Rs) Ct 4.25 The voltage of the soft start capacitor (CS) determines the soft start time (tss). When VCC voltage exceeds the startup voltage (Vth(st)), the soft start capacitor start to be charged by the current source (313nA). The switching frequency decreases linearly to fsw(nor) from fsw(pre) until the soft start capacitor voltage (VCS) touches 2V. Therefore the soft start duration time (tss) can be acquired by the following formula. Lighting Application With Gate Driver IC S

4 Figure 3. Frequency & Soft start capacitor voltage variation during soft start fsw, Vcs fsw (pre) fsw (nor) 2V tss No Lamp Protection When the voltage at pin #4 is lower than 2V, the gate drive output is off state, so the external power MOSFET stops switching. In no lamp protection circuit the dc link voltage is divided by a couple of resistors including both lamp filaments, and The divided voltage is applied to the pin #4 before the MOSFETs start switching. When in normal mode the average voltage of the V3 is the half of the dc link voltage (Vdd). So, in order to make stable start condition, the resistors are designed to make the voltage of V3 to be the half of the dc link voltage. Figure 4. Lamp detection resistor network DC Link Voltage (Vdd) R1 V2 R2 To pin #4 R3 V3 R4 C1 Lighting Application With Gate Driver IC S

5 S F Figure 5. Schematic circuit V1~V4 1N4007 LF2 LF1 R CON1 F1 MOV 7D471 XC1 104K/250V XC2 104K/250V N R1 47 μf /25V 1/2 150K C1 U1 6 2 S6500 1/2 150K 222/250VAC XC3 YC GND 15V/0.5W R2 R5 V8 1/4F 13K 1/4F 1M 1/4F 220K R3 R4 T2 B/T 160:12 S F C4 222K R6 1/4 47k 223J SR1 1/2 150K SD R111/4 0 C2 SD SD GR11/4 47 C3 1 μf /50V V5 BYV26C Q1 STK830 R10 1/4F 6.2K R7 1/2W 1 SR2 1/2 150K R8 1/4F 820K R9 1/4F 150K MC1 22 μf /450V C5 22 μf /25V CT 471J GR2 1/4 15K C μf /25V 4 5 U2 S6510 PT Driv er Q2 GR21/4 47 Q3 GR3 1/4 47 SR 1/4 470K C7 102J/630V V V10 15V/0.5W T1 LR1 1/4 1M LR2 1/4 47K C10 104K/630V PC1 C11 104K/630V CON2 Lighting Application With Gate Driver IC S

6 Table1. Component Listing 부품명특성부품기호부품명특성부품기호 P.C.B DIODE RECTIFIER CEM mm IN4007 (700V 1A) IC PFC V1,V2 V3,V4 IC DRIVER S6500 (SOP 8Pin) S6510 (SOP 8Pin) U1 U2 DIODE FAST RECOVERY BYV26C V5 VARISTOR 7D471 MOV DIODE SWITCHING SDS511 (85V 100mA) 이면작업 104K / 250V AC (0.22 μf ) 32W 104K / 250V AC (0.22 μf ) 36W 154K / 250V DC (0.15 μf ) 55W XC1,XC2 DIODE SWITCHING 1N4148 (75V 150mA 4nS) SD1,SD2,V9 104K / 250V DC (0.1 μf ) 32W 104K / 250V DC (0.1 μf ) 36W 154K / 250V DC (0.15 μf ) 55W XC3 DIODE ZENER DIODE ZENER 1/ 2W 15V 1/ 2W 15V V8 V10 154K / 630V DC (0.15 μf ) 105K / 63V DC (1.0 μf ) C10,C11 C3 1/ 2W Mini 150 kω R1,R2 SR1,SR2 CAP. NP 472J / 1.6kV DC ( μf ) 32W 472J / 1.6kV DC ( μf ) 36W 562J / 1.6kV DC ( μf ) 55W PC1 1/ 2W Mini 1Ω R7 CAP. NP 102J / 630V DC (0.001 μf ) C7 1 MΩ R3 CAP. PE 223J / 100V DC (0.022 μf ) 32W 223J / 100V DC (0.022 μf ) 36W 223J / 100V DC (0.022 μf ) 55W C2 820 kω 220 kω 150 kω R8 R4 R9 CAP. PE CAP. CERAMIC CAP. CERAMIC 332J / 100V DC ( μf ) 222K/250V AC ( μf ) 471J/50V DC ( μf ) C4 YC CT 13 kω R5 CAP. ELEC. 10 μf / 450V DC 32W 10 μf / 450V DC 36W 22 μf / 450V DC 55W MC1 15 kω 6.2 kω 820 kω 470 kω 47 kω 47 kω GR22 CAP. ELEC. 47 μf / 25V DC C1 R10 CAP. ELEC. 22 μf / 25V DC C5 LR1 CAP. ELEC μf / 50V DC C6 SR R6 LINE FILTER LINE FILTER SQ mH EE1614H 6mH LR2 TRANSFORMER EE1312 (56 : 56 : 56) PT LF1 LF2 47Ω GR1,GR2 GR3 TRANSFORMER EE2816(160:12) 2.0mH 32W EE2816(160:12) 1.7mH 36W EE2816(160:12) 1.7mH 55W T2 JUMPER WIRE IRON 10mm JP1,R11 INDUCTOR EE mH 32W EE mH 36W EE mH 55W T1 FUSE MOS FET FAP 2A/250V STK830 (500V 4.5A 1.5Ω) F1 TERMINAL BLOCK 3P CON1 Q1,Q2 Q3 TERMINAL BLOCK 4P CON2 Lighting Application With Gate Driver IC S

7 Soft Start function Ballast (S6510) NO Soft Start Normal Ballast Soft Start Time :1[Sec] Protection Section Vnd(S6510) Test Condition Cs Ct Rs VCC OUT1 OUT2 12V Test Point Test Point 3V ~ 1V Ldet GND 4V Ldet (Pin #3) Lighting Application With Gate Driver IC S