- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄200634 > UPC3025 Useage of Three-Terminal Regulators | User＇s Manual[05/2000] PDF資料下載
參數(shù)資料
| 型號(hào)： | UPC3025 |
| 英文描述： | Useage of Three-Terminal Regulators | User＇s Manual[05/2000] |
| 中文描述： | 使用三端穩(wěn)壓器|用戶手冊(cè)[05/2000] |
| 文件頁數(shù)： | 2/35頁 |
| 文件大小： | 187K |
| 代理商： | UPC3025 |
第1頁當(dāng)前第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁
User’s Manual G12702EJ8V0UM00
10
<5> Startup circuit
A power supply IC has an on-chip constant current circuit for use as an error amplifier load or for biasing the
reference voltage circuit. A constant current circuit, which consists of paired transistors, does not begin to
operate as long as the diode connected transistors are not in a steady bias state. A startup circuit therefore
is set up and it biases the active load at power-on to cause normal operation to begin whether the
temperature of the transistors is low or high.
<6> Overcurrent protection circuit
This is a protection circuit for preventing the load current from exceeding the current capacity of the output
stage power transistor. It restricts the base current of the output stage power transistor by biasing the current
restriction transistor more deeply in accordance with the voltage drop in the current detection resistor inserted
in the load current route.
<7> Limiting circuit for securing safe operating area (SOA)
The limiting circuit for securing SOA operates to cut down the output current if the voltage between input and
output (voltage between the collector and emitter of the output stage power transistor) becomes large so that
the safe operating area of the output stage power transistor is not exceeded.
If the voltage difference between input and output exceeds the breakdown voltage (7 to 8 V) of a Zener diode
connected between input and output, it limits the base current of the output stage power transistor by biasing
the current limiting transistor more deeply using the breakdown current.
Since the larger the voltage
difference between input and output the more the base current of the output stage power transistor is limited,
the load characteristic is a "foldback" type drooping characteristic as a result.
Figure 3-4 shows the parts of a general overcurrent protection circuit and limiting circuit for securing SOA.
Figure 3-4. Example of Overcurrent Protection Circuit and Limiting Circuit for Securing SOA
(
PC7800A Series)
Q16
Q15 : Current limiting
transistor
Q17
R11 : Current detection resistor
INPUT
Limiting circuit for securing SOA
OUTPUT
Output stage transistor
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| UPC1663B | Analog IC |
| UPC1663C | Analog IC |
| UPC1663P | Analog IC |
| UPC1664C | Analog IC |
| UPC1668B | Analog IC |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| UPC3025HB | 制造商:NEC 制造商全稱:NEC 功能描述:LOW-SATURATION STABILIZED POWER SUPPLY WITH ON/OFF FUNCTION (1 A OUTPUT) |
| UPC3025TJ | 制造商:NEC 制造商全稱:NEC 功能描述:LOW-SATURATION STABILIZED POWER SUPPLY WITH ON/OFF FUNCTION (1 A OUTPUT) |
| UPC3025TJ(AZ) | 制造商:Renesas Electronics Corporation 功能描述: |
| UPC3025TJ-E1 | 制造商:NEC 制造商全稱:NEC 功能描述:LOW-SATURATION STABILIZED POWER SUPPLY WITH ON/OFF FUNCTION (1 A OUTPUT) |
| UPC3025TJ-E2 | 制造商:NEC 制造商全稱:NEC 功能描述:LOW-SATURATION STABILIZED POWER SUPPLY WITH ON/OFF FUNCTION (1 A OUTPUT) |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。