BL8080 HIGH INTEGRATED PWM CONTROLLER GENERAL DISCRIPTION FEATURES The BL8080 is a PWM controller designed to drive high voltage NPN transistors. It integrates an oscillator, cycle-by-cycle current limit, thermal protection and over voltage protection, great reducing the number of external components and system level cost. Compared to conventional controller, BL8080 has a significantly smaller startup current of less than 20uA, which allows large startup resistor that enabes further power saving. The frequency can be adjusted from an external capcitor. At light load condition the frequency of BL8080 can be varied according to the load, which improves the light load efficiency. Low start up current Easy programmable frequency Compact SOT23-6 package Universal voltage range: 85VAC -264VAC Thermal shutdown Cycle by cycle current limit Slope current drive Low standby power consumption APPLICATIONS Cell phone charger DVD player power supply MP3 charger LED lighting driver TYPICAL APPLICATION CIRCUIT AC Input DC Output 6 CT OB 1 5 GND OE 2 4 FB VCC 3 LC8100 BL8080 Figure1: BL8080 Typical Application Circuit www.belling.com.cn 1 BL8080 BLOCK DIAGRAM Figure2: Block Diagram PIN CONFIGURATION SOT23-6 OB 1 6 CT OE 2 5 GND VCC 3 4 FB Figure3:BL8080 Top View PIN DISCRIPTIONS Pin # Name 1 OB 2 OE Output of the drive, connects this pin to the base of the external power transistor. Connects this pin to the emmiter of the external power transistor. 3 VCC The power supply. This pin provides power for the internal circuitry and driver. 4 FB Feedback. Need put a capacitor between this pin and the ground. 5 GND Ground. 6 CT Oscillator input pin. Need put a capacitor between this pin and the ground. The oscillator frequency varied with the capacitor value. www.belling.com.cn Description 2 BL8080 ORDERING INFORMATION MARKING INFORMATION BL8080 □ 1 □ 2 □ 3 Code Description Product Classification BL8080CB6TR Temperature & Rohs: 1 2 3 Marking C: -40~85°C, Pb Free Rohs Std. Package Type: B6: SOT-23-6 Packing Type: TR: Tape & Reel (Standard) AA Product code Y Year W Week 6 5 4 AAYW 1 2 3 ABSOLUTE MAXIMUM RATINGS Parameter Symbol Min Max Supply Power Voltage VCC -0.3 15 V -0.3 12 V 0.25 W Voltage at CT, FB, OB, OE Unit Power Dissipation PD Operating Junction Temperature TJ -40 150 ℃ Storage Temperature Ts -55 150 ℃ Electronic static discharg ESD 2000 V Notes: 1. Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. 2. All voltage values are given with respect to GND pin. RECOMMENDED OPERATING CONDITIONS The recommended operating conditions table defines the condition for acture device operation. Recommended operating conditions are specified to ensure the optimal performance to the datasheet specifications. Parameter Symbol Min Max Supply Power Voltage VCC 5.5 9 V Operating Ambient Temperature TA -25 85 ℃ www.belling.com.cn 3 Unit BL8080 ELECTRICAL CHARACTERISTICS (All the data tested under the condition: Ta=25℃, unless it is specially noted) Parameter Test Condition Min Type Max Unit Reference voltage Oscillator worked 2.4 2.5 2.6 V Line regulation VCC range 4.5V-9V 4 % Reference Section Load regulation Temperature coefficient 2 % 0.2 -40℃--120℃ mV/℃ Feedback Section Source current VFB=1V,Vcc=8V 500 Pull down resistor Sink current 600 700 uA Ω 23k VFB =2V, VCC=11V mA PFM threshold VPFM 1.5 1.8 2.0 V Oscillator stop threshold Vstart 0.8 1 1.2 V 42 45 48 KHZ Oscillator Section Frequency CCT=330pF Voltage stability 4.5V≤VCC≤9V Amplitude VCT peak to peak Temperature stability -40≤Ta≤125 -10 Falling slop time CCT=330pF 0.8 2.4 1 V +10 % 1.3 uS Source current 37 uA Sink current 500 uA PWM Section Max duty cycle 60 Min duty cycle 0 75 % % Current Sense Section Current sense voltage 0.6 Peak current limit IPK IPK temperature coefficient 450 -40≤Ta≤125 520 -10 Propagation delay time Minimum on time 0.5 V 600 mA 10 % 250 nS 1.2 uS Output Section OB source current IOC=0A (VCC=8V) IOC=0.5A 25 35 mA OB sink current VOB=1V VOB=2V 50 100 mA Power Section Startup current by OB Quiescent current 30 VCC=8V, VFB=0.6V(note1) VCC startup threshold www.belling.com.cn 8.4 4 8.8 50 uA 3.5 mA 9.2 V BL8080 ELECTRICAL CHARACTERISTICS (continued) Parameter Test Condition Min Type Max Unit VCC shut down threshold 4 4.5 5 V OVP threshold 9.5 10 10.5 V 135 145 ℃ Others Over temperature shut down threshold TYPICAL PERFORMANCE INFORMATION Figure4．Constant operating frequency Figure5. VCC Over Voltage Protection Point VS Temperature VS Temperature Figure6. VCC Startup Voltage VS Temperature www.belling.com.cn Figure7. VCC Shutdown Voltage VS Temperature 5 BL8080 TYPICAL PERFORMANCE INFORMATION Figure8. Reference Voltage VS Temperature Figure9. Oscillator Frequency VS Feedback Voltage TA=25 Figure10. Oscillator Frequency VS CT Cap www.belling.com.cn 6 BL8080 APPLICATION INFORMATION Start up Cycle by cycle current limit LC 8100 starts to work once VCC reaches the start up threshold voltage (typically 8.8V). The device has a build-in diode of which the anode connects to the OE pin and the cathod to the VCC pin. Through the external power transistor, the VCC storage capacitor can be charged, and the base current of the transistor is supplyed by a resistor connects to the DC bus.because the base current is amplified by transistor, this will greatlly reduce the cosumption. After start up the auxillary power supply take over. Cycle is terminated when the peak current exceeds 0.6A. In normal operation, Ipk should be less than 0.6A. When the power supply output is overload or the control loop is open, the internal OCP(over current protection) function circuit istriggered and shuts down the external transistor-pulling down the FB voltage in the rest time of this cycle to decrease the peak current.If FB voltage in one cycle is pulled down to 1.8V, then FB voltage will be clamped to this level till this cycle ended, if the next cycle the fault still exist, FB voltage will continue to be pull down to keep the transistor and transformer work at a save zone. Feedback and control Oscillator frequency(kHZ) The FB voltage value controls the peak current of primary side. The oscillator begins to work once VFB exceeds the threshold voltage of 1V. By comparing the voltage across the current sense resistor with a preset value of VFB*k (k is a coefficient less than 1), the internal comparator controls the on/off state of the transistorsin the cycle. BL8080 can automatically adjust the operating mode according to the load condition. If VFB is larger than 1.8V, BL8080 works at constant frequency mode which frequencyset by the CT capacitor, otherwisethe oscillator operates invaried frequency mode. VFM 1 1.8V FB Voltage(V) Figure11．Feedback Control of BL8080 www.belling.com.cn At the instant the power transistor is turn on, there usually exists a current spike through the transistor caused by primary side capacitor and secondary rectifier reverse recovery which can lead to incorrect OCP action.For this reason, BL8080 employs a leading edge blanking circuit to inhibit the current sense comparator for a short time after the transistor is on. Over Voltage Protection (OVP) BL8080 integrates VCC OVP circuit to improve the system stability. When the VCC voltage exceeds 10V due to abnormal condition, the OVP circuit is triggered and shut down the device. When VCC drops bellow UVLO, BL8080 starts again. As the output winding couples with the auxiliary winding, when the output voltage exceeds the set value, the auxiliary voltage rise linearly with the output voltage, if VCC exceeds 10V, PWM pulse is disabled to proventthe system from damage. Constant frequency 1V Leading edge blanking 7 BL8080 Over Temperature Protection (OTP) BL8080 integrates a temperature detection circuit that will shut down PWM output when the junction temperature exceeds 135℃. s When the temperature drops down and the VCC voltage is still over the UVLO voltage, the device resumes operation. Built-in Slope Compensation Under Voltage Lockout (UVLO) ICC Supply Current(mA) The turn-on and turn-off threshold voltage are fixed internally at 8.8V and 4.5V, respectivelly. Turn Off Turn On 4.5 8.8 Supply Voltage(V) VCC Figure12. UVLO of BL8080 During start up, the hold-up capacitor should be charged up to 8.8V by the start up resistor and www.belling.com.cn external transistor to enable the BL8080. The hold-up capacitor supplies VCC until the auxiliary winding of transformer takes over. When VCC drops below 4.5V, BL8080 stops work. This UVLO hysterisis ensures that the hold-up capacitor is adequate to supply VCC during normal operation. 8 The voltage across the current sense resistor is collected for current mode control and cycle by cycle current limit. Built-in slope compensation improves the stability and prevents sub-harmonic oscillations when the device works in continue conduction mode -especially when the duty cycle exceeds 50%. BL8080 Aplication Design Example BL8080 Figure13. 5W (5V/1A) Application Circuit BOM Designator Part Type Designator Part Type D1 IN5822 R1,R9 100 D2,D3,D4,D6,D7 IN4007 R2,R6 3M D5 IN4148 R3 270K C1 1nF R5 5.1K C2 1nF,250V R7 10 C3,C4 470uF,10V R8 300 C5 6.8uF,400V R10 1K C6 3.3uF,400V R11 20K C7 22uF,16V R12,R13 27K C8 33nF L1c 1mH C9 10nF(optional) L2 1.5uH C10 330pF L3 10uH C11 0.1uF U1 BL8080 Q1 MJE13003 U2 PC817 IC2 TL431 T1 EE16 RF1 10, 2W www.belling.com.cn 9 BL8080 PACKAGE INFORMATION Package Type www.belling.com.cn SOT23-6 Number of devices per reel 10 3000