BD9G101G-EVK-101

ROHM Switching Regulator Solutions Evaluation Board for ROHM’s BD9G101G Buck Switching Regulator with Built-In Power MOSFET AEY59-D1-0001 BD9G101G (5V | 0.5A Output) ●Introduction This user’s guide will explain the steps necessary to operate and evaluate ROHM’s BD9G101G step-down switching regulator using the BD9G101G evaluation board. Board layout recommendations, operating procedures, application data, and bill of materials are included. ●Description This evaluation board has been specifically developed to evaluate the BD9G101G non-synchronous buck DC/DC converter with integrated 45V/800mΩ power MOSFET. Features include wide input (6V to 42V) and output (1V to VCC x 0.7V) voltage ranges and a switching frequency of 1.5MHz. Multiple protection functions are also built in, including a soft start circuit that prevents inrush current during startup, UVLO (Under Voltage Lock Out), TSD (Thermal Shutdown), and OCP (Overcurrent Protection). An EN pin allows for simple ON/OFF control to reduce standby current consumption. ●Applications Industrial distributed power systems Automotive and battery-powered equipment ●Evaluation Board Operating Limits and Absolute Maximum Ratings Parameter Symbol Limit MIN TYP MAX - 42 Unit Conditions Supply Voltage BD9G1010G VCC 6 (*1) V Output Voltage / Current BD9G101G VOUT 1.0(*2) 5 BD9G101G IOUT - 0.5 VINx0.7 - (*3) V *Set by R1 and R2 A (*1)Restricted by maxduty ,Ron and BST-UVLO. (*2)Restricted by minimum on pulse typ. 100nsec (*3)Restricted by maxduty ,Ron and BST-UVLO. ●Evaluation Board Below are images of the BD9G101G evaluation board. Component selection and board layout guidelines are provided in the BD9G101G datasheet. VOUT GND VCC ENABLE H: Inactive (IC àOFF) L: Active (IC àON) BD9G101G Eval Board (Back) BD9G101G Eval Board (Front) www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. 2016.04 - Rev.002 1 User’s Guide ●Board Schematic ●Board I/O Below is a reference application circuit showing the inputs VCC and EN and the output (VOUT @5V/0.5A) L1: 10uH 680 3.9k ●Operating Procedures 1. 2. 3. Connect GND to a GND pin on the evaluation board Connect VCC to the VCC pin. i. Note: The EN pin is pulled HIGH as a default. EN needs to be set to LOW for IC operation. The output voltage can be measured from the VOUT pin on the evaluation board. Output current can be measured with a proper load at VOUT. Note: The IC could be damaged if hot plugged. Therefore, make sure to power down the system before removing or connecting the BD9G101G evaluation board. www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. 2016.04 - Rev.002 2 User’s Guide ●Reference Application Data The below graphs show the efficiency, frequency response, and load characteristics of the BD9G101G eval board. EN 10V/div EN 10V/div Lx 10V/div Lx 10V/div VOUT 1V/div VOUT 1V/div IOUT 0.2A/div IOUT 0.2A/div Start-up Characteristics VIN=8V, IOUT=0mA ,VOUT=5V Start-up Characteristics VIN=8V, IOUT=500mA, VOUT=5V EN 20V/div Lx 10V/div EN 20V/div Lx 10V/div VOUT 1V/div VOUT 1V/div IOUT 0.2A/div IOUT 0.2A/div Start-up Characteristics VIN=12V, IOUT=0mA, VOUT=5V Start-up Characteristics VIN=12V, IOUT=500mA ,VOUT=5V EN 10V/div EN 10V/div Lx 10V/div Lx 10V/div VOUT 1V/div VOUT 1V/div IOUT 0.2A/div IOUT 0.2A/div Start-up Characteristics VIN=42V, IOUT=0mA, VOUT=5V Start-up Characteristics VIN=42V, IOUT=500mA, VOUT=5V www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. 2016.04 - Rev.002 3 User’s Guide Io [100mA/div] Vout(AC) [100mV/div] Vout:offset 5V 10mV/div Overshoot Voltage:46mV UnderOvershoot Voltage:43mV Load Response Io=50mA⇔200mA Lx Switching/ Vout Ripple Io = 20mA Vout:offset 5V 10mV/div Phase Gain Lx Switching/ Vout Ripple Io=200mA Frequency Response Io=100mA, VOUT=5V 100 90 Vin=12V 80 Vin=8V 70 Phase Efficiency η [%] 60 Gain Vin=24V 50 Vin=42V 40 30 20 10 0 1 Output Current [mA] 100 Electric Power Conversion Rate Io=500mA, VOUT=5V Frequency Response Io=500mA, VOUT=5V www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. 10 2016.04 - Rev.002 4 1000 User’s Guide ●Application Components Selection Method (1) Inductors A shield type with low DCR (DC resistance component) that satisfies the current rating (current value Ipeak below) is recommended. The inductance value has a significant effect on the inductor ripple current, which becomes the source of output ripple. As shown in the formula below, this ripple current can be made smaller by increasing the L value of the coil and/or the switching frequency. Ipeak =Iout + ⊿IL/2 [A] ⊿IL= Vin-Vout L (1) Vout × Vin × 1 f [A] ΔIL Fig 17: Inductor Current (2) (⊿IL: Output Ripple Current, f: Switching Frequency) Please carry out inductor ripple design with a target of 20 to 50% of the maximum input current. For the BD9G101G, the below inductors are recommended within the 4.7μH to 15μH range. Recommended Inductor TOKO DE4518C Series TAIYO YUDEN NR4018 Series (2) Input Capacitor To reduce input ripple voltage, please connect a low ESR ceramic capacitor near the VCC pin. For the BD9G101G, we recommend a capacitance less than 4.7μF. And in the event an electrolytic capacitor is used, mount a 1μF ceramic capacitor in parallel to prevent oscillation. (3) Output Capacitor To reduce output ripple, a low ESR ceramic capacitor is recommended. And in addition to taking into account DC bias characteristics, please provide sufficient margin with respect to the absolute maximum rated output voltage. 1 Vpp=⊿IL× 2π×f×Co + ⊿IL×RESR [V] (3) Please design in a way that it is held within Capacity Ripple Voltage. In the BD9G101G, it is recommended a ceramic capacitor over 10μF. (4) Output voltage setting The internal reference voltage of the ERROR AMP is 0.75V. The output voltage is determined from the following formula. Vout Csp R1 Vo= FB R2 0.75V (R1+R2) + + R2 ×0.75[V] ・・・ (4) Fig 18: Output voltage setting However, in order to prevent BSTUVLO operation during reduced power and light loads, please ensure that the sum R1+R2 for the output resistance satisfies the following formula. R1 + R 2 ≤ Vout × 103 　・・・　 (8) (5) ・・・ Example output resistance settings: 5V output voltage → R1=3.9kΩ, R2=0.68kΩ 12V output voltage → R1=7.5kΩ, R2=0.51kΩ www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. 2016.04 - Rev.002 5 User’s Guide (5)Feed-forward capacitor Csp Please mount feed-forward capacitor in parallel to output resistance R1. In order that a feed-forward capacitor may adjust the loop characteristic by adding the pair of a pole and zero to the loop characteristic. A phase margin is improved and transient response speed improves. The feed-forward capacitor Csp should use the value near the following formulas. 4.7k × 0.15　　　 [uF ]　　・・・　 (9) (6) ・・・ R1 Example Csp settings: 5V output voltage → R1=3.9kΩ, R2=0.68kΩ, Csp=0.1μF or 0.22μF 12V output voltage → R1=7.5kΩ, R2=0.51kΩ, Csp=0.1μF Csp = To prevent BSTUVLO operation during reduced power and light loads, we recommend connecting a feed-forward capacitor Csp in parallel with the output resister R1. The feed-forward capacitor improves phase margin and transient response by adding a zero-pole pair to the loop characteristics. This works to limit output fluctuation. For the feed-forward capacitor Csp, use an output resistance value near to the following formula. Through the above measures, BSTUVLO will not activate under light loads and VIN-VOUT