Document
Datasheet
4.2V to 18V Input 1ch
Boost Controller
BD9306AFVM
General Description BD9306AFVM is a 1-channel DC/DC converter controller. A Step-up DC/DC converter can be configured. In addition, it has a built-in master-slave function which improves synchronization.
Features 1ch PWM Controlled DC/DC Converter Controller Built-in Soft Start Function Built-in Master / Slave Function Protection Circuits: Under Voltage Lockout Protection Circuit Thermal Shutdown Circuit Short Protection Circuit of Timer Latch type
Key Specifications
Power Supply Voltage Range:
4.2V to 18V
Error Amplifier Feed Back Voltage:
1.25±1.6%
Oscillating Frequency Range: 100kHz to 800kHz
Standby Current:
0µA(Typ)
Operating Temperature Range: -40°C to +85°C
Package
W(Typ) x D(Typ) x H(Max)
Applications ・TV, Power Supply for the TFT-LCD Panels used for LCD TVs, Back Lights ・DSC, DVC, Printer, DVD ,DVD Recorder, Generally Consumer Equipments etc.
MSOP8 2.90mm x 4.00mm x 0.90mm
Typical Application Circuit
FB 8
1.25V
Err
OSC
1 RT
20Ω
10000pF
3.9kΩ COMP 7
GND 6
VCccC 5
Soft Start
Timer 0 Latch -
Shut Down
Vref UV-LO TSD
Vcc
Shut Down
VCC
10uF
47uH V Io=30mA
PWM
DRV
ENABLE
2 CT
200pF
3 ENB
10kΩ
4 GD
VVCCCC
Figure 1. Typical Application Circuit
20uF
200kΩ
15kΩ
VVoOUT
1kΩ 100pF
○Product structure:Silicon monolithic integrated circuit
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© 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・14・001
○This product has no designed protection against radioactive rays
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TSZ02201-0323AAJ00640-1-2 13.Nov.2015 Rev.001
BD9306AFVM
Pin Configuration
TOP VIEW
Pin Descriptions Pin No
1 2 3 4 5 6 7 8
Block Diagram
Pin Name
RT CT ENB GD VCC GND COMP FB
Function
External timing resistor pin External timing capacitor pin Control pin Gate drive output pin Power supply pin Ground pin Error amp output pin Error amp inversion input pin
FB 8
1.25V
Err
COMP 7
GND 6
VCVCcc 5
Soft Start Timer 0 Latch -
Shut Down
Vref UV-LO TSD
Vcc
Shut Down
V Io=30mA
OSC
1 RT
PWM
DRV
2 CT
ENABLE
3 ENB
4 GD
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© 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001
2/20
TSZ02201-0323AAJ00640-1-2 13.Nov.2015 Rev.001
BD9306AFVM
Block Operation
1. Error Amplifier (Err) It compares a reference voltage of 1.25V (TYP) and the output feedback voltage. This block produces the COMP terminal voltage that determines the duty cycle.
2. Oscillator (OSC) This block determines the switching frequency by RT and CT values. The triangular wave is determined by RT and CT.
3. PWM The duty cycle is determined by comparing the output of Error amplifier and the angular wave of Oscillator. The switching Duty of BD9306AFVM is limited by the maximum duty ratio that is determined by the internal part, and will not be up to 100%.
4. DRV This block drives the gate of the external power FET by the PWM switching Duty.
5. VREF This block outputs the internal reference voltage of 2.5V (TYP). This circuit’s reference voltage is controlled (ON / OFF) by the ENB terminal.
6. Protection Circuits (UVLO / TSD) UVLO (low-voltage Lock Out circuit) shuts down the circuits when the voltage is below 3.5V (MIN). TSD (temperature protection circuit) shuts down the IC when the temperature reaches 175°C (TYP).
7. Soft Start Circuit The Soft Start Circuit limits the current when the output voltage is slowly increasing during start-up. Through this, the overshoot of output voltage and current sinking can be prevented.
8. Timer Latch It is an output short protection circuit that detects if the output of error amplifier (COMP voltage) is more than 1.7V (TYP). If the COMP voltage becomes more than 1.7V, the counter begins to operate. The LATCH is locked when the counter counts to 2200 and the GD output shuts down. The frequency of counter is determined by RT and CT. Once the LATCH was locked, the GD output will not operate until it is restarted by ENB or VCC. If the output short is removed while the Timer latch is counting, the counter will be reset.
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© 2015 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001
3/20
TSZ02201-0323AAJ00640-1-2 13.Nov.2015 Rev.001
BD9306AFVM
Absolute Maximum Ratings (Ta = 25°C)
Parameter
Symbol
Limit
Unit
Power Supply Voltage (Note 2) Power Dissipation
VCC Pd
20 0.58 (Note 1)
V W
Operating Temperature Range
Topr
-40 to +85
°C
Storage Temperature Range
Tstg
-55 to +150
°C
Maximum Junction Temperature
Tjmax
150
°C
(Note 1) When mounted on a glass epoxy 4-layer board (70 mm x 70 mm x 1.6 mm). Derate by 4.7 mW/°C for Ta over 25°C. (Note 2) Must not exceed Pd. Caution: Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit between pins. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is operated over the absolute maximum ratings.
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