Single-chip Type with Built-in FET Switching Regulators High-efficiency Step-up Switching Regulators with Built-in Power MOSFET BD8152FVM,BD8158FVM No.11027ECT20 ●Description BD8152FVM,BD8158FVM are the 1-channel step-up switching regulator which builds in the low voltage FET. Input voltage is 2.5 V to 5.5 V (BD8152FVM), 2.1V to 5.5V(BD8158FVM) realizing the low consumption power. High accuracy feedback voltage 1% is established and the brightness dispersion of TFT-LCD panel is suppressed. ●Features 1) Current mode PWM system 2) Input voltage is 2.5 V to 5.5 V (BD8152FVM), 2.1 V to 5.5 V (BD8158FVM, providing the low power input) 3) Switching frequency is variable as 600 kHz/1,200 kHz. 4) Built-in 0.25 Ω power switch 5) Feedback voltage 1.245 1% 6) Built-in under-voltage lockout protection circuit 7) Built-in overcurrent protection circuit 8) Built-in thermal shutdown circuit ●Applications 7 to 17 inches panels for the satellite navigation system, laptop PC TFT-LCD panels ●Absolute maximum ratings (Ta = 25℃) Parameter Symbol Limit Unit Power supply voltage Vcc 7 V Power dissipation Pd 588* mW Operating temperature range BD8152FVM −40 to +85 Topr BD8158FVM Storage temperature range ℃ −40 to +125 Tstg −55 to +150 ℃ Switch pin current Isw 1.5** A Switch pin voltage Vsw 15 V Tjmax 150 ℃ Maximum junction temperature * Reduced by 4.7 mW/℃ over 25℃, when mounted on a glass epoxy board (70 mm 70 mm 1.6 mm). ** Must not exceed Pd. ●Recommended Operating Ranges (Ta = 25℃) Parameter Symbol Limit Min. Typ. Max. Unit Power supply voltage (BD8152FVM) Vcc 2.5 3.3 5.5 V Power supply voltage (BD8158FVM) Vcc 2.1 2.5 4.0(5.5)* V Switch current ISW - - 1.4 A Switch pin voltage VSW - - 14 V *Specified at 600kHz switching operating. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 1/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM ●Electrical Characteristics BD8152FVM (Unless otherwise specified, Ta = 25℃; Vcc = 3.3 V; ENB = 3.3 V) Limit Parameter Symbol Unit Conditions Min. Typ. Max. [triangular waveform oscillator] Oscillating frequency 1 FOSC1 540 600 660 kHz FCLK = 0 V Oscillating frequency 2 FOSC2 1.08 1.20 1.32 MHz FCLK = Vcc [Overcurrent protection circuit] Overcurrent limit ISW 2 A [Soft start circuit] SS source current ISO 6 10 14 µA Vss = 0.5 V [Under-voltage lockout protection circuit] Off threshold voltage VUTOFF 2.1 2.2 2.3 V On threshold voltage VUTON 2.0 2.1 2.2 V [Error amp] Input bias current IB 0.1 0.5 µA Feedback voltage VFB 1.232 1.245 1.258 V Buffer [Output] ON resistance RON 250 380 mΩ *Isw = 1 A Max. duty ratio DMAX 72 80 88 % RL = 100 Ω [ENB] ENB on voltage VON Vcc0.7 Vcc V ENB off voltage VOFF 0 Vcc0.3 V [Overall] Standby current ISTB 0 10 µA VENB = 0 V Average consumption current ICC 1.2 2.4 mA no switching * This product is not designed for protection against radio active rays. Design guarantee (No total shipment inspection is made.) ●Electrical Characteristics BD8158FVM (Unless otherwise specified, Ta = 25℃; Vcc = 2.5 V; ENB = 2.5 V) Limit Parameter Symbol Unit Conditions Min. Typ. Max. [triangular waveform oscillator] Oscillating frequency 1 FOSC1 480 600 720 kHz FCLK = 0 V Oscillating frequency 2 FOSC2 0.96 1.20 1.44 MHz FCLK = Vcc [Overcurrent protection circuit] Overcurrent limit ISW 2 A [Soft start circuit] SS source current ISO 6 10 14 µA Vss = 0.5 V [Under-voltage lockout protection circuit] Off threshold voltage VUTOFF 1.7 1.8 1.9 V On threshold voltage VUTON 1.6 1.7 1.8 V [Error amp] Input bias current IB 0.1 0.5 µA Feedback voltage VFB 1.232 1.245 1.258 V Buffer [Output] ON resistance RON 250 mΩ *Isw = 1 A Max. duty ratio DMAX 85 % RL = 100 Ω [ENB] ENB on voltage VON Vcc0.7 Vcc V ENB off voltage VOFF 0 Vcc0.3 V [Overall] Standby current ISTB 0 10 µA VENB = 0 V Average consumption current ICC 1.2 2.4 mA no switching * This product is not designed for protection against radio active rays. Design guarantee (No total shipment inspection is made.) www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 2/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM 2.000 1.75 1.500 1.50 1.25 -40°C 1.00 25°C 0.75 0.50 125°C 0.25 1.260 1.000 125°C 0.500 0.000 -0.500 25°C -1.000 0 -1.500 1 2 3 1.255 1.250 1.245 1.240 1.235 1.230 0 4 1 SUPPLY VOLTAGE:Vcc [V] 2 3 4 -40 SUPPLY VOLTAGE:Vcc [V] -8 -12 -16 0 0.5 1 1.5 1500 1.2 1.0 0.8 0.2 0 2 4 -40 Fig. 5 Reference Voltage vs Power Supply Voltage -40°C 1.0 1.5 2.0 2.5 3.0 FCLK VOLTAGE:VFCLK[V] Fig. 7 FCLK Pin Current www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 35 60 85 110 Fig. 6 Switching Frequency Temperature 100 15 50 125°C 10 ICOMP[uA] ENB CURRENT:IENB[uA] 25°C 10 VCOMP[V] 20 0.5 -15 SUPPLY VOLTAGE:VCC[V] 10 0 0.0 VFCLK=GND 500 0.4 Fig. 4 SS Source Current 5 1000 0.6 0 125°C 110 VFCLK=VCC 1.4 SS VOLTAGE:VSS[V] 15 85 1.6 2 20 60 2000 0.0 -20 35 BD8158FVM 1.8 ICOMP[uA] REFERENCE VOLTAGE:VREF[V -4 10 Fig. 3 Reference Voltage vs Temperature 2.0 0 -15 AMBIENT TEMPERATURE:Ta [℃] Fig. 2 Standby Current Fig. 1 Total Supply Current SS CURRENT:ISS[uA] -40°C -2.000 0.00 FCLK CURRENT:IFCLK[uA] REFERENCE VOLTAGE:VREF[V] 2.00 STANDBY CURRENT:Icc [uA] SUPPLY CURRENT:Icc [mA] ●Reference Data (Unless otherwise specified, Ta = 25℃) 25°C 5 0 -50 -40°C 0 0.0 -100 0.5 1.0 1.5 2.0 2.5 ENB VOLTAGE:VENB[V] Fig. 8 ENB Pin Current 3/17 3.0 1.0 1.1 1.2 1.3 1.4 1.5 VCOMP[V] Fig. 9 COMP Sinking vs Source Current 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM ●Reference Data (Unless otherwise specified, Ta = 25℃) 100 90 90 90 85 EFFICIENCY [%] EFFICIENCY [%] Max Duty [%] 95 80 VCC = 2.5 V f = 1200 kHz 70 VCC = 2.5 V f = 600 kHz 80 70 60 60 BD8152FVM BD8158FVM 80 -40 -15 10 35 60 85 50 0.05 110 0.2 0.25 50 0.05 0.3 0.15 0.25 0.35 0.45 OUTPUT CURRENT:Io[A] Fig. 11 Vcc = 2.5V Power Efficiency Fig. 10 Max. Duty Ratio Temperature Fig. 12 Vcc = 5V Power Efficiency 0.8 MAXIMUM CURRENT:IOMAX[A] 100 90 80 70 60 BD8158FVM 50 2.0 2.5 3.0 3.5 BD8158FVM 0.4 Vo F = 600 kHz 20 us 0.2 2.4 2.8 3.2 3.6 4.0 SUPPLY VOLTAGE:Vcc[V] SUPPLY VOLTAGE:Vcc[V] Fig. 13 Power Efficiency vs Power Supply Voltage Fig. 14 Max. Load Current vs Power Supply Voltage 9 9 8.8 8.8 OUTPUT VOLTAGE:Vo[V] 8.4 8.2 8 2.0 Fig. 15 Load Response Waveform 9 Vcc = 2.5 V 8.6 2.5 3.0 3.5 4.0 SUPPLY VOLTAGE:Vcc[V] Fig. 16 Output Voltage Line Regulation www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 100 mV F = 1200 kHz 0 2.0 4.0 Io = 100 mA Io = 0 mA 0.6 OUTPUT VOLTAGE:Vo[V] EFFICIENCY [%] 0.15 OUTPUT CURRENT:Io[A] AMBIENT TEMPERATURE:Ta [℃] OUTPUT VOLTAGE:Vo[V] 0.1 8.6 8.4 8.2 8 0.0 BD8158FVM 0.1 LOAD CURRENT:Io[A] Fig. 17 Output Voltage Load Regulation 1 4/17 1.0 8.8 Vcc=5V 8.6 8.4 8.2 8 0.0 BD8152FVM 0.1 1.0 LOAD CURRENT:Io[A] Fig. 18 Output Voltage Load Regulation 2 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM ●Block Diagram SS FCLK VCC SW 8 7 6 5 CURRENT SENSE OSC + Set SW FCLK SOFT START LOGIC Reset DRV SDWN PWM + - Vcc SS SLOPE OCP UVLO/TSD 1.245V GND ENB FB COMP ERR - + TOP VIEW VREF 1 2 3 4 COMP FB ENB GND Fig. 19 Pin Arrangement Diagram and Block Diagram ●Pin Assignment Diagram and Function Pin No. Pin name 2 FB Function Error amp inversion input pin 3 ENB Control input pin 4 GND Ground pin 5 SW N-channel power FET drain output 6 Vcc Power supply input pin 7 FCLK 8 SS Frequency switching pin Soft start current output pin www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 5/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM ●Description of Operation of Each Block D1 RB161M-20 10uH L1 VOUT 9V VCC C0 10uF C1 10uF 8 C2 0.01uF 6 7 SS SLOPE 5 VCC FCLK SW CURRENT SENSE OSC + Set SOFT START LOGIC Reset DRV SDWN PWM + - OCP UVLO/TSD ERR - + VREF 1.245V COMP FB 1 C4 100pF ENB 2 3 GND 4 ＊ R3 5.1kΩ C3 3300pF R1 R2 18kΩ 110kΩ Fig. 20 Application Circuit Diagram Example Error amp (ERR) This is the circuit to compare the reference voltage 1.245 V (Typ.) and the feedback voltage of output voltage. Switching duty is decided by the COMP pin voltage which is the comparison result. At the time of start, since the soft start is operated by the SS pin voltage, the COMP pin voltage is limited to the SS pin voltage. Oscillator (OSC) This block generates the oscillating frequency. It is possible to select 600 kHz/1.2 MHz (Typ.) by the FCLK pin. SLOPE This block generates the triangular waveform from the clock generated by OSC. Generated triangular waveform is sent to the PWM comparator. PWM Output COMP voltage of the error amp and the triangular waveform of the SLOPE block are compared to decide the switching duty. Since the switching duty is limited by the maximum duty ratio which is decided internally, it does not become 100%. Reference voltage (VREF) This block generates the internal reference voltage of 1.245 V (Typ.). Protection circuit (UVLO/TSD) UVLO (under-voltage lockout protection circuit) shuts down the circuits when the voltage is 2.2 V (TYP.BD8152FVM),1.8 V (TYP.BD8158FVM) or lower. Thermal shutdown circuit shuts down IC at 175℃ (Typ.) and recovers at 160℃ (Typ.). Overcurrent protection circuit (OCP) Current flowing to the power FET is detected by voltage at the CURRENT SENSE and the overcurrent protection operates at 3 A (Typ.). When the overcurrent protection operates, switching is turned off and the SS pin capacity is discharged. Soft start circuit Since the output voltage rises gradually while restricting the current at the time of startup, it is possible to prevent the output voltage overshoot or the inrush current. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 6/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM ●Timing Chart Startup sequence VCC ENB SS SW VO Fig. 21 Startup Sequence Waveform Overcurrent protection operating 2.5V VCC,ENB SS SW VO IO Fig. 22 Overcurrent Protection Operating Waveform www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 7/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM ●Selecting Application Components (1) Setting the output L constant The coil L to use for output is decided by the rating current ILR and input current maximum value IINMAX of the coil. VCC IINMAX + IL should not IL reach the rating value level L IL ILR Vo IINMAX average current Co t Fig. 24 Output Application Circuit Diagram Fig. 23 Coil current waveform Adjust so that IINMAX + ∆IL does not reach the rating current value ILR. At this time, ∆IL can be obtained by the following equation. 1 Vo - Vcc 1 [A] Where, f is the switching frequency. ∆IL= Vcc L Vo f Set with sufficient margin because the coil L value may have the dispersion of approx. 30%. If the coil current exceeds the rating current ILR of the coil, it may damage the IC internal element. BD8152FVM,BD8158FVM use the current mode DC/DC converter control and has the optimized design at the coil value. The following coil values are recommended from the aspects of power efficiency, response and safety. When the coil out of this range is selected, the stable continual operation is not guaranteed such as the switching waveform becomes irregular. Please pay attention to it. Switching frequency: L = 10 uH to 22 uH at 600 kHz Switching frequency: L = 4.7 uH to 15 uH at 1,200 kHz (2) Setting the output capacitor For the capacitor C to use for the output, select the capacitor which has the larger value in the ripple voltage VPP allowance value and the drop voltage allowance value at the time of sudden load change. Output ripple voltage is decided by the following equation. ∆VPP = ILMAX RESR + 1 fCo Vcc Vo (ILMAX - ∆IL 2 ) [V] Where, f is the switching frequency. Perform setting so that the voltage is within the allowable ripple voltage range. For the drop voltage during sudden load change; VDR, please perform the rough calculation by the following equation. VDR = ∆I Co 10u sec [V] However, 10 s is the rough calculation value of the DC/DC response speed. Please set the capacitance considering the sufficient margin so that these two values are within the standard value range. (3) Selecting the input capacitor Since the peak current flows between the input and output at the DC/DC converter, a capacitor is required to install at the input side. For this reason, the low ESR capacitor is recommended as an input capacitor which has the value more than 10μF and less than 100 mΩ. If a capacitor out of this range is selected, the excessive ripple voltage is superposed on the input voltage, accordingly it may cause the malfunction of IC. However these conditions may vary according to the load current, input voltage, output voltage, inductance and switching frequency. Be sure to perform the margin check using the actual product. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 8/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM (4) Selecting the output rectification diode Schottky barrier diode is recommended as the rectification diode to use at the DC/DC converter output stage. Select the diode paying attention to the max. inductor current and max. output voltage. < Rating current of diode Max. Inductor current IINMAX + ∆IL < Rating voltage of diode Max. output voltage VOMAX Since each parameter has 30% to 40% of dispersion, be sure to design providing sufficient margins. (5) Design of the feedback resistor constant Refer to the following equation to set the feedback resistor. As the setting range, 10 kΩ to 330 kΩ is recommended. If the resistor is set to 10 kΩ or lower, it causes the reduction of power efficiency. If it is set to 330 kΩ or larger, the offset voltage becomes larger by the input bias current 0.4 µA (Typ.) in the internal error amp. Step-up Vo = R8 + R9 R9 1.245 [V] Reference voltage 1.245 V Vo R8 ＋ ERR 2 FB R9 － Fig. 25 Feedback Resistor Setting As the capacitance, 0.001 µF to 0.1 µF is recommended. If the capacitance is set to 0.001 µF or lower, the overshooting may occur on the output voltage. If the capacitance is set to 0.1 µF or larger, the excessive back current flow may occur in the internal parasitic elements when the power is turned off and it may damage IC. When the capacitor to 0.1 µF or larger is used, be sure to insert a diode to VCC in series, or a bypass diode between the SS pin and VCC. 10 DELAY TIME[ms] (6) Setting the soft start time Soft start is required to prevent the coil current at the time of startup from increasing and the overshoot of the output voltage at the starting time. Fig.26 shows the relation between the capacitance and soft start time. Please refer to it to set the capacitance. 1 0.1 0.01 0.001 0.01 0.1 SS CAPACITANCE[uF] Bypass diode Fig. 26 SS Pin Capacitance vs Delay Time Back current prevention diode VCC Output pin Fig. 27 Bypass Diode Example When there is the startup relation (sequences) with other power supplies, be sure to use the high accuracy product (such as X5R). Soft start time may vary according to the input voltage, output voltage, loads, coils and output capacity. Be sure to verify the operation using the actual product. (7) Setting the ENB pin When the ENB pin is set to Hi, the internal circuit becomes active and the DC/DC converter starts operating. When it is set to Low, the shut down is activated and all circuits will be turned off. (8) Setting the frequency by FCLK It is possible to change the switching frequency by setting the FCLK pin to Hi or Low. When it is set to Low, the product operates at 600 kHz (Typ.). When it is set to Hi, the product operates at 1,200 kHz (Typ.). www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 9/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM (9)Setting RC, CC of the phase compensation circuit In the current mode control, since the coil current is controlled, a pole (phase lag) made by the CR filter composed of the output capacitor and load resistor will be created in the low frequency range, and a zero (phase lead) by the output capacitor and ESR of capacitor will be created in the high frequency range. In this case, to cancel the pole of the power amplifier, it is easy to compensate by adding the zero point with CC and RC to the output from the error amp as shown in the illustration. Open loop gain fp = fp(Min) A fp(Max) fz (ESR) = 0 Gain 【dB】 1 [Hz] 2 R O CO 1 [Hz] 2 E SR CO lOUT Min fz(ESR) lOUT Max Pole at the power amplification stage When the output current reduces, the load resistance Ro increases and the pole frequency lowers. 0 Phase 【deg】 -90 fp (Min) = Error amp phase compensation fz (Max) = A 【dB】 0 0 【deg】-90 fp (Amp.) = Fig. 28 Gain vs Phase Vcc,PVcc Cin 2 ROMin CO [Hz] At heavy-load 1 [Hz] 2 R c Cc Ro ESR SW COMP Rc 1 [Hz] At light-load Vo L VCC 2 ROMax C O Zero at the power amplification stage When the output capacitor is set larger, the pole frequency lowers but the zero frequency will not change. (This is because the capacitor ESR becomes 1/2 when the capacitor becomes 2 times.) Gain Phase 1 Co GND,PGND Cc Fig. 29 Application Circuit Diagram It is possible to realize the stable feedback loop by canceling the pole fp (Min.), which is created by the output capacitor and load resistor, with CR zero compensation of the error amp as shown below. fz (Amp.) = fp (Min.) 1 2 Rc Cc = 1 [Hz] 2 Romax Co As the setting range for the resistor, 1 kΩ to 10 kΩ is recommended. When the resistor is set to 1 kΩ or lower, the effect by phase compensation becomes low and it may cause the oscillation of output voltage. When it is set to 10 kΩ or larger, the COMP pin becomes Hi-Z and the switching noise becomes easy to superpose. Therefore the stable switching pulse cannot be generated and the irregular ripple voltage may be generated on the output voltage. As the setting range for the capacitance, 3,300 pF to 10,000 pF is recommended. When the capacitance is set to 3,300 pF or lower, the irregular ripple voltage may be generated on the output voltage due to the effect of switching noise. When it is set to 10,000 pF or larger, the response becomes worse and the output voltage fluctuation becomes large. Accordingly it may require the output capacitor which is larger than the necessary value. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 10/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM ●Application Examples Although ROHM is sure that the application examples are recommendable ones, further check the characteristics of components that require high precision before using them. When a circuit is used modifying the externally connected circuit constant, be sure to decide allowing sufficient margins considering the dispersion of values by external parts as well as our IC including not only the static but also the transient characteristic.For the patent, we have not acquired the sufficient confirmation. Please acknowledge the status. (1) When the charge pump is removed from the DC/DC converter to make it 3-channel output mode: It is possible to create the charge pump by using the switching operation of DC/DC converter. When the application shown in the following diagram is used, 1-channel DC/DC converter output, 1-channel positive side charge pump and 1-channel negative side charge pump can be output as a total of 3-channels. 0.1µF 0.1µF D1 RB161M-20 L1 10µH V CC Vo 9V DAN217U C0 10µF 1µF C1 10µF 8 SS C2 0.01µF 6 7 VCC FCLK SLOPE 0.1µF SW CU R REN T SENSE OSC 1µF 1kΩ 2SD2657k 5 VGH UDZ Series DAN217U 1µF 100kΩ + Set SOFT START LOGIC Reset PWM + - FB R3 5.1kΩ C3 3300pF 1µF VREF ENB 2 VGL 100kΩ UVLO/TSD 1.245V 1 2SB1695k UDZ Series OCP ERR - + COMP 1µF 1kΩ DRV SDWN 3 GND 4 R1 R2 18kΩ 110kΩ Fig. 30 3ch Application Circuit Diagram Example www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 11/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM (2) When the output voltage is set to 0 V: Since the switch does not exist between the input and output in the application using the step-up type DC/DC converter, the output voltage is generated even if the IC is turned off. When it is intended to keep the output voltage 0 V until IC operates, insert the switch as shown in the following circuit diagram. D1 RB161M-20 1kΩ 10uH L1 Vo VCC 10uF C1 10uF 8 C2 0.01uF 6 7 SS SLOPE 5 VCC FCLK Switches of PNP or PFET SW CURRENT SENSE OSC + Set SOFT START LOGIC Reset DRV SDWN PWM + - OCP UVLO/TSD ERR - + VREF 1.245V COMP FB 1 ENB 2 GND 3 4 R1 R3 5.1kΩ C3 3300pF R2 18kΩ 110kΩ Fig. 31 Switch Application Circuit Diagram Example ●Application Examples (3) When the circuit is intended to operate at the lower voltage than the IC operating range: Although the recommended operating range of IC starts from 2.5 V / 2.1 V (BD8152FVM,BD8158FVM), it is possible to continue operating by composing the self-energizing type step-up DC/DC converter application even if the input voltage lowered than 2.1 V. This example is recommended for the application with battery input. D1 RB161M-20 10uH L1 VCC 2.0V Vo 3.3V 10uF C1 10uF 8 C2 0.01uF 6 7 SS SLOPE 5 VCC FCLK SW CURRENT SENSE OSC + Set SOFT START LOGIC Reset DRV SDWN PWM + - OCP UVLO/TSD ERR - + VREF 1.245V COMP FB 1 R3 5.1kΩ C3 3300pF ENB 2 3 GND 4 R1 R2 18kΩ 110kΩ Fig. 32 Self-Energizing Application Circuit Diagram Example www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 12/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM (4) SEPIC type application When it is intended to compose the step-up type DC/DC converter, the SEPIC type application is recommended. Since the switching voltage is generated by the value of input voltage + output voltage, pay utmost attention to the withstand voltage of SW pin. D1 4.7uF 10uH L1 RB161M-20 Vo VCC 10uF 10uH C1 10uF 8 6 7 SS C2 0.01uF SLOPE 5 VCC FCLK SW CURRENT SENSE OSC + Set SOFT START LOGIC DRV SDWN Reset PWM + - OCP UVLO/TSD ERR - + VREF 1.245V COMP FB 1 ENB 2 GND 3 4 R1 R3 5.1kΩ C3 3300pF R2 18kΩ 110kΩ Fig. 33 SEPIC Application Circuit Diagram Example (5) When the Supply Voltage is over 4.0 V (BD8158FVM only) The Capacitor C4 is inserted to COMP pin, and it operates when the Supply Voltage is over 4.0 V. In this case, Switching Frequency is limited to 600kHz. D1 RB161M-20 10uH L1 Vo 10uF C1 10uF 8 C2 0.01uF 6 7 SS SLOPE 5 VCC FCLK SW CURRENT SENSE OSC + Set SOFT START LOGIC Reset DRV SDWN PWM + - OCP UVLO/TSD ERR - + VREF 1.245V COMP FB 1 C4 100pF R3 5.1kΩ C3 3300pF ENB 2 3 GND 4 R1 R2 18kΩ 110kΩ Fig.34 Circuit Diagram Example(Supply Voltage over 4.0 V ) www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 13/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM ●I/O Equivalent Circuit Diagrams 1.COMP 5.SW Vcc 2.FB 8.SS Vcc Vcc Vcc 3.ENB 7.FCLK Vcc 130kΩ Fig. 34 I/O Equivalent Circuit Diagram ●Notes of Use 1) Absolute maximum ratings Use of the IC in excess of absolute maximum ratings such as the applied voltage or operating temperature range may result in IC damage. Assumptions should not be made regarding the state of the IC (short mode or open mode) when such damage is suffered. A physical safety measure such as a fuse should be implemented when use of the IC in a special mode where the absolute maximum ratings may be exceeded is anticipated. 2) GND potential Ensure a minimum GND pin potential in all operating conditions. 3) Setting of heat Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions. 4) Pin short and mistake fitting Use caution when orienting and positioning the IC for mounting on an application board. Improper mounting may result in damage to the IC. Shorts between output pins or between output pins and the power supply and GND pins caused by the presence of a foreign object may result in damage to the IC. 5) Action in strong magnetic field Use caution when using the IC in the presence of a strong magnetic field as doing so may cause the IC to malfunction. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 14/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM 6) Testing on application boards When testing the IC on an application board, connecting a capacitor to a pin with low impedance subjects the IC to stress. Always discharge capacitors after each process or step. Ground the IC during assembly steps as an antistatic measure, and use similar caution when transporting or storing the IC. Always turn the IC's power supply off before connecting it to or removing it from a jig or fixture during the inspection process. 7) Ground wiring patterns When using both small signal and large current GND patterns, it is recommended to isolate the two ground patterns, placing a single ground point at the application's reference point so that the pattern wiring resistance and voltage variations caused by large currents do not cause variations in the small signal ground voltage. Be careful not to change the GND wiring patterns of any external components. 8) This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated. P/N junctions are formed at the intersection of these P layers with the N layers of other elements to create a variety of parasitic elements. For example, when the resistors and transistors are connected to the pins as shown in Fig. 35, a parasitic diode or a transistor operates by inversing the pin voltage and GND voltage. The formation of parasitic elements as a result of the relationships of the potentials of different pins is an inevitable result of the IC's architecture. The operation of parasitic elements can cause interference with circuit operation as well as IC malfunction and damage. For these reasons, it is necessary to use caution so that the IC is not used in a way that will trigger the operation of parasitic elements, such as the application of voltages lower than the GND (P substrate) voltage to input and output pins. Resistor Transistor (NPN) (Pin B) C C B E ～ ～ ～ ～ (Pin B) ～ ～ B (Pin A) E GND N N N Parasitic elements P＋ N N (Pin A) P substrate Parasitic element GND P P＋ ～ ～ P＋ N P GND N P P＋ Parasitic elements Parasitic element GND GND Fig.35 Example of a Simple Monolithic IC 9) Overcurrent protection circuits An overcurrent protection circuit designed according to the output current is incorporated for the prevention of IC destruction that may result in the event of load shortning. This protection circuit is effective in preventing damage due to sudden and unexpected accidents. However, the IC should not be used in applications characterized by the continuous operation or transitioning of the protection circuits. At the time of thermal designing, keep in mind that the current capability has negative characteristics to temperatures. 10) Thermal shutdown circuit (TSD) This IC incorporates a built-in TSD circuit for the protection from thermal destruction. The IC should be used within the specified power dissipation range. However, in the event that the IC continues to be operated in excess of its power dissipation limits, the attendant rise in the chip's temperature Tj will trigger the temperature protection circuit to turn off all output power elements. The circuit automatically resets once the chip's temperature Tj drops. Operation of the TSD circuit presumes that the IC's absolute maximum ratings have been exceeded. Application designs should never make use of the TSD circuit. 11) Testing on application boards At the time of inspection of the installation boards, when the capacitor is connected to the pin with low impedance, be sure to discharge electricity per process because it may load stresses to the IC. Always turn the IC's power supply off before connecting it to or removing it from a jig or fixture during the inspection process. Ground the IC during assembly steps as an antistatic measure, and use similar caution when transporting or storing the IC. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 15/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM POWER DISSIPATION:Pd[mW] ●Power Dissipation Reduction 800 On 70×70×1.6mm Board 588 600 400 200 BD8152FVM 0 25 50 75 85 BD8158FVM 100 125 150 AMBIENT TEMPERATURE[℃] Fig. 36 Power Dissipation Reduction www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 16/17 2011.08 - Rev.C Technical Note BD8152FVM, BD8158FVM ●Ordering part number B D 8 1 5 2 Part No. 8152 8158 Part No. F V M - Package FVM:MSOP8 E 2 Packaging and forming specification TR: Embossed tape and reel (MSOP8) MSOP8 <Tape and Reel information> 2.8±0.1 4.0±0.2 8 7 6 5 0.6±0.2 +6° 4° −4° 0.29±0.15 2.9±0.1 (MAX 3.25 include BURR) Tape Embossed carrier tape Quantity 3000pcs Direction of feed TR The direction is the 1pin of product is at the upper right when you hold ( reel on the left hand and you pull out the tape on the right hand ) 1 2 3 4 1PIN MARK 1pin +0.05 0.145 –0.03 0.475 0.08±0.05 0.75±0.05 0.9MAX S +0.05 0.22 –0.04 0.08 S Direction of feed 0.65 Reel (Unit : mm) www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 17/17 ∗ Order quantity needs to be multiple of the minimum quantity. 2011.08 - Rev.C Notice Notes No copying or reproduction of this document, in part or in whole, is permitted without the consent of ROHM Co.,Ltd. The content specified herein is subject to change for improvement without notice. The content specified herein is for the purpose of introducing ROHM's products (hereinafter "Products"). If you wish to use any such Product, please be sure to refer to the specifications, which can be obtained from ROHM upon request. Examples of application circuits, circuit constants and any other information contained herein illustrate the standard usage and operations of the Products. The peripheral conditions must be taken into account when designing circuits for mass production. Great care was taken in ensuring the accuracy of the information specified in this document. However, should you incur any damage arising from any inaccuracy or misprint of such information, ROHM shall bear no responsibility for such damage. The technical information specified herein is intended only to show the typical functions of and examples of application circuits for the Products. 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If a Product is intended to be used for any such special purpose, please contact a ROHM sales representative before purchasing. If you intend to export or ship overseas any Product or technology specified herein that may be controlled under the Foreign Exchange and the Foreign Trade Law, you will be required to obtain a license or permit under the Law. Thank you for your accessing to ROHM product informations. More detail product informations and catalogs are available, please contact us. ROHM Customer Support System http://www.rohm.com/contact/ www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. R0039A