推荐几款高性价比的DCDC转换方案-BL8033.pdfELECTRICAL PERFORMANCE

文件名称: 推荐几款高性价比的DCDC转换方案-BL8033.pdf

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详细说明：推荐几款高性价比的DCDC转换方案-BL8033.pdfELECTRICAL PERFORMANCE Tested under L=4.7uH, TA=25C, unless otherwise specified Efficiency VS lout Efficiency vS lout (Vout=1.2V) (Vout=3.3V 100% 100% 80% 80% 70% 70% 60% 60% 550% 550% vin=5V 20% Vin=5v e Vin=6V Vin=12V Vin=12V 10% 10% Vin=16V Vin=16v 0% 0% 000.51.0 2.0 3 0.00.51.01.52. lout(A) lout(A) Efficiency VS lout yout ys, lout (Vout=5.0V) (Vout=1. 2V) 1.30 322 70% 1111 0505 20% vin=6V Vin=12V 10% vin=12V Vin=16V 0.90 0.5 1.0 1.52.02.530 0.0 1.0 2.0 3.0 lout (A) lout(A) Vout ys, lout yout ys. lout (Vout=3. 3V) (Vout=5.0V 3.45 3.40 55555 543210 3.35 3.30 5444 8 4 3.15 4 6543 3.10 Vin=6v vin=6V vin=l2V Vin=12v Vin=16V Vin=16V 3.00 4.0 0.0 1.0 2.0 3.0 0.0 0.5 1.0 1.5 2.0 lout(A) lout(A) www.belling.com.cn Efficiency vs. Vin Vout vs. vin lout=lA lout=lA 3.40 Vout=3,3V 3.35 95% 3.30 94% G93% 当325 92% 91% 3.20 3.15 88% 8 12 16 10 14 Vin v) Vin (v) Load transient Load transient Vin=12v out=3.3V lout=0. 01 3A Vin=12V, Vout=3.3V, lout=0.53A Ch2-Vout, ch 4--IL Ch2-Vout Ch4--IL 21003 45302 0Cs50自动t4500 00s500 标楼式标准模式 2n nMsa/ 通辽通过无信号值 245n 133mV BLOCK DIAGRAM ≤RSEN Regulator Current sense Bootstrap Regulator[ HOST Osci lator HS 1: sw Current Limit On Time Contro VCC Comparator Reference Drier Error Amplifier GND www.belling.com.cn DETAILED DESCRIPTION Internal Regulator starts first generating stable reference voltage and The bl8033 is a current mode step down DC/DC currents, and then the internal regulator is enabled converter that provides excellent transient The regulator provides stable supply for the response with no extra external compensation remaining circuitries. Three events can shut down components. This device contains an internal, low the chip: EN low, VIN low and thermal shutdown resistance, high voltage power MOSFET, and In the shutdown procedure, the signaling path is operates at a high 500k operating frequency to first blocked to avoid any fault triggering. The ensure a compact, high efficiency design with COMP voltage and the internal supply rail are then excellent AC and dC performance pulled down The floating driver is not subject to this shutdown command Error Amplifier The error amplifier compares the FB pin voltage APPLICATIONS INFORMATION with the internal FB reference (VaB) and outputs a current proportional to the difference between the Setting Output Voltages two. this output current is then used to charge or The external resistor divider is used to set the discharge the internal compensation network to output voltage(see Ty pical Application on page 1 form the Comp voltage which is used to control The feedback resistor r1 also sets the feed back the power mosfet current. the optimized internal loop bandwidth with the internal compensation compensation network minimizes the external capacitor. Choose R1 to be around 300kQ for component counts and simplifies the control loop optimal transient response. R2 is then given by esign R1 Internal Soft-Start The soft-start is important for many applications because it eliminates power-up initialization □wour problems. The controlled voltage ramp of the 只2 output also reduces peak inrush current during start-up, minimizing start-up transient events to the input power bus Selecting the Inductor Over-Current-Protection and Hiccup Use a 2.2HH-to-l0HH inductor with a DC current The bl8033 has a cycle-by-cycle over-current rating of at least 25% percent higher than the limit for when the inductor current peak value maximum load current for most applications. For exceeds the set current -limit threshold first highest efficiency, select an inductor with a DC when the output voltage drops until Fb falls resistance less than 15m2. For most designs below the Under-Voltage Uv threshold erive the inductance value from the following (typically 140mv) to trigger a Uv event, the equation bl8033 enters hiccup mode to periodically restart OUT X(V ⅠN the part This protection mode is especially useful VN×△l,×fosc when the output is dead-shorted to ground. this Where AlL is the inductor ripple current. choose greatly reduces the average short-circuit current an inductor current approximately 30% of the to alleviate thermal issues and to protect the maximum load current the maximum inductor regulator. The bl8033 exits hiccup mode once peak current is the overcurrent condition is removed △In Startup and Shutdown MAX LOAD If both VIN and en are higher than their appropriate Under light-load conditions (below 100mA),use thresholds, the chip starts. The reference block a larger inductor to improve efficiency www.belling.com.cn Selecting the Output Capacitor ground and gnd pin as short and wide as The output capacitor (C2 maintains the DC possible output voltage. Use ceramic, tantalum, or low- 2 Keep the connection between the input Esr electrolytic capacitors. Use low ESR capacitor and vin pin as short and wide as capacitors to limit the output voltage ripple possible. Estimate the output voltage ripple with 3Use short and direct feedback connections Place the feedback resistors and compensation △Vor=ou×1-7×|REsR8×sxc2l components as close to the chip as possible fs 4) Route Sw away from sensitive analog areas Where L is the inductor value and resr is the such as FB equivalent series resistance(ESR) of the output capacitor. For ceramic capacitors the capacitance dominates the impedance at the switching frequency and causes most of the output voltage ripple. For simplification estimate the output voltage ripple with: OUT ×1 OUT △VoUr8×f2XL×C For tantalum or electrolytic capacitors the esr dominates the impedance at the switching frequency. For simplification, the output ripple can be approximated with △V OUT OUT fs x X RESR IN The characteristics of the output capacitor also VOUT GND affect the stability of the regulation system the bL8033 can be optimized for a wide range of capacitance and esr values C BOARD LAYOUT VIN OGND PCB layout is very important to achieve stable operation. For best results, use the following guidelines and figures as reference 1)Keep the connection between the input www.belling.com.cn TYPICAL APPLICATION CIRCUITS 工 GND 6.8uH GND BL8033 SW 5V/3A VOUT C2A RE 入A NS 100K R7 GND GND ENO R2 NS 7. 63k GND GND Figure3. 12VVIN, 5V/3A 工2工 0.1 C4 GND 25 luF GND END sW4,7山H GND BL8033 Sw R3 100k NS R7 10k 402k EN FB GND NS GND GND Figure4. 12V VIN, 3.3V/3A VN BST 22F 25V 1PF GNI 4.7pH GND BL8033 Sw 2.5V/3A VOUT C2A 10Ck GND GND E EN FB v GND NS 19.1k Figure5. 12V VIN, 2. 5V/3A www.belling.com.cn R4 VINE VIN ESI OR GND GND SW 3.3Hh BL8033 1. 8V/3A VOUT R3 R5 AS 10K R7 GND 40 EN EN GND t NS 324k GND NS Figure6. 12V VIN, 1.8V/3A VIN BST C6 工工 GND GND Sy 2.2uH BL8033 SW 1.2V/3A VOUT R3 C2A R 100k NS 30k 205k EN FB GND NS GND NS GND Figure7. 12V VIN, 1.2V/3A PACKAGE OUTLINE L Package 5OT23-6 Devices per reel 3000 Unit Package specification 2.90.2 +0.2 1.90.2 0to0.1 0.2 www.belling.com.cn

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