参数资料
| 型号： | BD9778HFP-TR |
| 厂商： | Rohm Semiconductor |
| 文件页数： | 7/19页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 2A HRP7 |
| 标准包装： | 1 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1 V ~ 35 V |
| 输入电压： | 7 V ~ 35 V |
| 频率 - 开关： | 50kHz ~ 500kHz |
| 电流 - 输出： | 2A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | TO-263-8，D²Pak（7 引线+接片），TO-263CA |
| 包装： | 标准包装 |
| 供应商设备封装： | HRP7 |
| 其它名称： | BD9778HFP-DKR BD9778HFP-DKR-ND BD9778HFPDKR |
BD9778F, BD9778HFP, BD9001F, BD9781HFP
Technical Note
Description of operations
ERROR AMP
The ERROR AMP block is an error amplifier used to input the reference voltage (1 V typ.) and the INV pin voltage. The output
FB pin controls the switching duty and output voltage Vo. These INV and FB pins are externally mounted to facilitate phase
compensation. Inserting a capacitor and resistor between these pins enables adjustment of phase margin. (Refer to
recommended examples on page 11.)
SOF T START
The SOFT START block provides a function to prevent the overshoot of the output voltage Vo through gradually increasing
the normal rotation input of the error amplifier when power supply turns ON to gradually increase the switching Duty. The soft
start time is set to 5 msec (Typ.).
ON/OFF(BD9778F/HF P,BD9781HFP)
Setting the EN pin to 0.8 V or less makes it possible to shut down the circuit. Standby current is set to 0 μA (Typ.).
Furthermore, on the BD9781HFP, applying a pulse having a frequency higher than set oscillation frequency to the EN/SYNC
pin allows for external synchronization (up to +50% of the set frequency).
PWM COM PARATOR
The PWM COMPARATOR block is a comparator to make comparison between the FB pin and internal triangular wave and
output a switching pulse.
The switching pulse duty varies with the FB value and can be set in the range of 0 to 100%.
OSC(Oscillator)
The OSC block is a circuit to generate a triangular wave that is to be input in the PWM comparator. Connecting a resistor to
the RT pin enables setting of oscillation frequency.
TSD(Thermal Shut Down)
In order to prevent thermal destruction/thermal runaway of this IC, the TSD block will turn OFF the output when the chip
temperature reaches approximately 150?C or more. When the chip temperature falls to a specified level, the output will be
reset. However, since the TSD is designed to protect the IC, the chip junction temperature should be provided with the thermal
shutdown detection temperature of less than approximately 150?C.
CURREN T LIMIT
While the output POWER P-ch MOS FET is ON, if the voltage between drain and source (ON resistance ￥ load current)
exceeds the reference voltage internally set with the IC, this block will turn OFF the output to latch. The overcurrent protection
detection values have been set as shown below:
BD9781HFP . . . 8A(Typ.)
BD9001F,BD9778F/HFP . . . 4A(Typ.)
Furthermore, since this overcurrent protection is an automatically reset, after the output is turned OFF and latched, the latch will
be reset with the RESET signal output by each oscillation frequency.
However, this protection circuit is only effective in preventing destruction from sudden accident. It does not support for the
continuous operation of the protection circuit (e.g. if a load, which significantly exceeds the output current capacitance, is
normally connected). Furthermore, since the overcurrent protection detection value has negative temperature characteristics,
consider thermal design.
www.rohm.com
? 2010 ROHM Co., Ltd. All rights reserved.
7/16
2010.02 - Rev. B
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相关代理商/技术参数 |
参数描述 |
|---|---|
| BD978 | 制造商:INFINEON 制造商全称:Infineon Technologies AG 功能描述:PNP SILICON DARLINGTON TRANSISTORS |
| BD9781HFP | 制造商:ROHM 制造商全称:Rohm 功能描述:Flexible Step-down Switching Regulators with Built-in Power MOSFET |
| BD9781HFP-TR | 功能描述:开关变换器、稳压器与控制器 IC REG SW 4A P-CH MOSF STDN RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
| BD979 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:TRANSISTOR | BJT | DARLINGTON | NPN | 80V V(BR)CEO | 1A I(C) | TO-202 |
| BD980 | 制造商:INFINEON 制造商全称:Infineon Technologies AG 功能描述:PNP SILICON DARLINGTON TRANSISTORS |
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