BL8305A BALLAST CONTROL IC The ballast control IC BL8305A is an improved version of the BL8301. The BL8305A provides more functionality and is easier to use than previous IC BL8301. The BL8305A optimizes the compatibility of driving MOSFET half-bridge (MHF MHF) MHF or Bipolar half-bridge (BHF BHF). BHF Especially for Bipolar half-bridge, the BL8305A can automatically adjust the base current intensity (BCI BCI AutoAuto-Adj), Adj and guarantee that the half-bridge is in the optimum condition and reduces the power loss of half-bridge. It also improves the load adaptive of bipolar half-bridge. The BL8305A changes the timing component connection structure according to BL8301, so it is easier to design simply dimming products. The BL8305A has fully protections and all pins have Latch immunity and ESD protection, available in both PDIP14 and SOP14 packages. FEATURES Driving both MHF and BHF Automatically adjusting the BCI of BHF Programmable preheat frequency, preheat time and run frequency Comprehensive protection Micro power startup less than 150uA Latch immunity and ESD protection BRIEF INTRODUCTION 1. The BL8305A automatically provides a dead time 3us for BHF and 1.2us for MHF. 2. The BL8305A features include on power preheat and ignition. Preheat frequency, preheat time and run mode frequency are all programmable by external components. 3. Comprehensive protections such as protection from over current of Half-bridge, filament failures, ignition failure, end of life, detecting base current of half-bridge and so on. 4. The BL8305A have an internal power regulator at 6.35V and micro power startup less than 150uA. 5. The BL8305A is a low cost design for ballast with few external components. http://www.belling.com.cn -1Total 8 Pages 8/28/2006 BL8305A BALLAST CONTROL IC 6. The BL8305A is available in both PDIP14 and SOP14 packages. All pins have Latch immunity and ESD protection. APPLICATION INFORMATION 400V IN4148 Rstart 1n RHV 430K 15V 1M 13005 BL8305A Rp2 Rt Ct 0.1u Rpre HV Rt Ct LD FD Cpre Pro POFF 2 Ro 30 22 22n 13005 10 Co 47n 2 22n IN4148 100K GND Cp 620K C1 470p 4.7u 17.2K 100K Rp1 OUT1 OUT2 0.1u Vcc Vdc 175K FR107 10 100n 2mH T8 FR107 36W 8.2n 0.1u 2 Attention: This shematic for T8 36W only, other types lamp should change some components Fig. 1 400V IN4148 Rstart 1M 1n 15V IRF830 100 BL8305A Rp2 Rt Ct 0.1u Cp Vdc OUT2 Rpre Rt HV LD Ct FD Cpre POFF Pro GND Co 1u IRF830 100n 2mH 100 T8 36W 620K C1 470p 4.7u 17.2K 100K Rp1 OUT1 0.1u 175K Vcc 8.2n 0.1u 2 Attention: This shematic for T8 36W only, other types lamp should change some components Fig. 2 http://www.belling.com.cn -2Total 8 Pages 8/28/2006 BL8305A BALLAST CONTROL IC BLOCK DIAGRAM LEAD ASSIGNMENTS & DEFINITION Pin# 1 2 3 Symbol VCC VDC Rpre 4 5 6 7 8 9 10 11 12 13 14 Rt Ct Cpre POff GND Pro FD LD HV OUT2 OUT1 http://www.belling.com.cn Description Power Supply 6.3V regulator output Preheat frequency timing voltage Oscillator timing resistor Oscillator timing capacitor Preheat timing capacitor End of preheat output IC power &signal ground Current sensing input Filament detection input Window discriminator input Half-bridge output sense OUTPUT2 OUTPUT1 -3Total 8 Pages 8/28/2006 BL8305A BALLAST CONTROL IC FUNCTION DESCRIPTION StartStart-up and Power Supply When the VCC is below the turn-on threshold of the IC, the BL8305A is in the low power consumption mode, oscillator and half-bridge are shut off. The start-up capacitor (C1) is charged by 400V DC-BUS through resistor (Rstart). The charge current (Icharge) is the current through Rstart minus the start-up current (IQstart) drawn by the IC. So the choice basis of starting resistance Rstart is: In most abominable cases, the current guaranteeing to pass Rstart is IQStart of twice at least. Once the capacitor voltage on VCC reaches the start-up threshold, the IC turns on and the output turns on. The rectified current charges the capacitor at about 15V. The recommended capacitor value is 22uF. Preheat Mode, Ignition Mode and Run Mode The Preheat frequency, preheat time and run mode frequency of BL8305A are all programmable by external components. The typical frequency vs. time curve is as the picture shows. The preheat time is set by the external capacitor Cp. An internal current source ICpreCharge charges Cp when the IC started. The frequency remains at eh preheat frequency until the voltage on Cp over the threshold voltage. After preheat the BL8305A begins to igniting the lamp. The total preheat http://www.belling.com.cn time is: -4Total 8 Pages 8/28/2006 BL8305A BALLAST CONTROL IC T preheat = 0.203 × C p × 10 7 − 0.249 * voltage(VRpre) VR Pr e = at R pre 2 R pre1 + R pre 2 pin3, the R p2 R p1 + R p 2 preheat sec。Preheat frequency is set by the frequency is: f pre = VRpre 1 .6 × f run ， × 6.35 . The run mode oscillating frequency is determined by the timing resistor RT and timing capacitor Ct, f run = 0.374 。 Rt × Ct Drive BHF or MHF When driving BHF, a transformer with two secondary magnifies the output current of BL8305A and the half-bridge is drive by the magnified current. The output voltage of half-bridge is divided by the resistor RHV and an internal resistor about 40Kohm in the PIN HV and the BL8305A senses this waveform, and automatically adjusts the BCI. The BCI Auto-Adj is enabled at about 1 sec after the ignition. As showing in the figure, if BCI is appropriate, the output of BL8305A will be remain as the black line; if BCI is low, the output of BL8305A will be increase as the dashed line; if BCI is over driving, the output of BL8305A will be decrease as the dashdotted line. http://www.belling.com.cn -5Total 8 Pages 8/28/2006 BL8305A BALLAST CONTROL IC Driving MHF the output connection is shows as the figure above. The driving voltage is coupled from out1 by a 1:2 transformer in order to separate the IC form high voltage. In MHF driving configuration, HV is connect to GND directly, hence whether the BL8305A in preheat, ignition or run mode the output of BL8305A is fixed. Fault Protection The BL8305A provides 3 leads to sensing fault: Pro (PIN9), FD (PIN10) and LD (PIN11). The Pro PIN is enabled at the IC turns on. Once the voltage at this pin exceeds Vpro (0.55V), the IC enters fault mode and both outputs are latched in the ‘low’ state. The FD PIN is used for filament detection; the IC will be restart when FD received a pulse. LD is a window discriminator. The high threshold is 4.3V, and the low threshold is 2.0V. LD has a pull up resistor 200K to Vdc, and a pull down resistor 200K to GND, in order to get a bias voltage 3.2V for the LD PIN. At the end of ignition mode, LD will become effective after 1s delay(1s delay is used for avoid ignition’s burr). Once the BL8305A enters the fault mode, the IC will lock the state until VCC recycles back below the shut down threshold or the filament detection PIN, SD, receives a pulse. http://www.belling.com.cn -6Total 8 Pages 8/28/2006 BL8305A BALLAST CONTROL IC Filament Preheat Voltage Remove The BL8305A provides a control signal (PIN Poff) to switch off the filament preheat voltage. When it done with the ignition and turns into run mode, Poff will output a high level after about 1s delay (drive ability 20mA). This high level can close the switch K and turn off the filament voltage. ABSOLUTE ABSOLUTE MAXIMUM RATIONS Absolute maximum ratings indicate sustained limits beyond which damage to the device may occur. All voltages parameter are absolute voltages referenced to GND, all current are defined positive into any lead. Parameter Min. Max Units Symbol Definition Vcc(1) Supply voltage --- 30 V VRpre Preheat frequency timing voltage 1 7 V IRt Oscillator output current --- 1 mA VPro Current sensing voltage -0.3 Vdc V Iout1 Output current of Out1 200 mA Iout2 Output current of Out2 200 mA TS Storage temperature 150 ℃ -55 Note 1: Only for BHF mode. In MHF mode VCC should less than 15V. RECOMMENDED OPERATING CONDITIONS Parameter Min. Typ. Max. Units Symbol Definition Vcc Supply voltage -- 15 -- V VRpre Preheat frequency timing voltage 1 -- 4 V IRt Oscillator output current 20 82 200 uA VPro Current sensing voltage 0 -- Vdc V ELECTRICAL CHARACTERISTICS TA=25℃，VCC=15V，Rpre1=150K，Rpre2=100K，Rt=17.7K，Ct=470pF，Cp=0.1uF，Vpro=0V， ＶLD1= 3.2V，VHV=0 Parameters Symbol Min. Typ. Max. Units Test Condition Definition Power Supply Characteristics VCCon Power on Voltage - 13.7 - V VCC rising from 0V VCCoff Shut down voltage - 10 - V VCC falling from 15V VDC Internal power regulator output - 6.35 - V VCC=15V http://www.belling.com.cn -7Total 8 Pages 8/28/2006 BL8305A BALLAST CONTROL IC voltage IVDC Internal power regulator output current IQStart Low power startup current --- IQFault Fault protection quiescent current IQVCC Quiescent current Oscillator Characteristics fosc Oscillator frequency VCT Oscillator capacitor voltage Preheat Characteristics ICpreCharge Cpre charge current 10 mA VCC=15V --- 150 uA VCC<VCCon --- --- 250 uA Pro > 0.55V or LD < 2.0V or LD > 4.3V --- 3 --- mA Out1、Out2 Without load 1 --- 300 KHz --- 45 --- KHz 4 V 2 --- 0.45 --- uA --- 0.97 --- uA ICpreDis Cpre discharge current Fpre Preheat frequency 71 KHz Tpre Preheat time 1.4 S Tign Ignition time 140 mS VCpreFault Cpre voltage under fault protection --- Driver Output Characteristics (HV=GND) Vout1p-p p-p output voltage of 13 out1 fosc = 45 KHz 0 --- V --- 15 V Iout > 100mA Iout1 p-p output current of out1 - --- 200 mA Vout1p-p > 13V Vout2p-p p-p output voltage of out1 13 --- 15 V Iout > 100mA Iout2 p-p output current of out1 - --- 200 mA Vout1p-p > 13V TdeadMOS Dead time for MHF mode 1.2 us TdeadBip Dead time for MHF mode 3.0 us Protection Characteristics VPro Over current sensing threshold - 0.55 - V VLDup High threshold of LD - 4.3 - V VLDdn Low threshold of LD - 2.0 - V http://www.belling.com.cn -8Total 8 Pages HV＝6.3V 8/28/2006