- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄374598 > RM4391D (RAYTHEON SEMICONDUCTOR) Inverting and Step-Down Switching Regulator PDF資料下載
參數(shù)資料
| 型號： | RM4391D |
| 廠商： | RAYTHEON SEMICONDUCTOR |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Inverting and Step-Down Switching Regulator |
| 中文描述： | 0.375 A SWITCHING REGULATOR, CDIP8 |
| 文件頁數(shù)： | 8/22頁 |
| 文件大?。?/td> | 153K |
| 代理商： | RM4391D |
PRODUCT SPECIFICATION
RC4391
8
When power is first applied, the output filter capacitor is dis-
charged so the ground lead potential starts at 0V. The refer-
ence voltage is forced to +1.25V above the ground lead and
pulls the feedback input (pin 8) more positive than the
ground lead. This positive voltage forces the control network
to begin pulsing the switch transistor. As the switching
action pumps up the output voltage, the ground lead rises
with the output until the voltage on the ground lead is equal
to the feedback voltage. At that point, the control network
reduces the time on time of the switch to maintain a constant
output.
This control network will vary the on time of the switch in
response to changes in load current or battery voltage (see
Figure 12). If the load current increases (waveform C), then
the transistor will remain on (waveformD) for a longer por-
tion of the oscillator cycle, (waveform B), thus allowing the
inductor current (waveform E) to build up to a higher peak
value. The duty cycle of the switch transistor varies in
response to changes in load and line.
Design Equations
The inductor value and timing capacitor (C
X
) value must be
carefully tailored to the input voltage, input voltage range,
output voltage, and load current requirements of the applica-
tion. The key to the problem is to select the correct inductor
value for a given oscillator frequency, such that the inductor
current rises to a high enough peak value (I
MAX
) to meet the
average load current drain. The selection of this inductor
value must take into account the variation of oscillator
frequency from unit to unit and the drift of frequency over
temperature. Use
±
30% as a maximum variation of oscillator
frequency.
Important Note: This circuit must have a minimum load
3
1 mA always connected.
Figure 11. Step-Down Regulator – Standard Circuit
C2
C1
OSC
+1.25V
REF/Bias
RC4391
65-2475
REF
V
Q1
Q2
Cx
A
B
R1
R2
+Vs
1N914
F
E
D1
+V = (1.25V) ( R2
R1
D
C
F
+V
OUT
Lx
LBR
LBD
C
X
GND
L
X
+V
S
V
REF
V
FB
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| RM500DZ-24 | HIGH POWER GENERAL USE INSULATED TYPE |
| RM500DZ-2H | HIGH POWER GENERAL USE INSULATED TYPE |
| RM500DZ-H | HIGH POWER GENERAL USE INSULATED TYPE |
| RM500UZ-24 | BATTERY SEALED LEAD ACID 12V 5AH |
| RM500UZ-2H | BATTERY SEALED LEAD ACID 12V 7AH |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| RM4-3C90 | 制造商:FERROXCUBE 制造商全稱:Ferroxcube International Holding B.V. 功能描述:RM, RM/I, RM/ILP cores and accessories |
| RM4-3D3 | 制造商:FERROXCUBE 制造商全稱:Ferroxcube International Holding B.V. 功能描述:RM, RM/I, RM/ILP cores and |
| RM4-3D3-A63 | 制造商:FERROXCUBE 制造商全稱:Ferroxcube International Holding B.V. 功能描述:RM, RM/I, RM/ILP cores and |
| RM4-3D3-E40 | 制造商:FERROXCUBE 制造商全稱:Ferroxcube International Holding B.V. 功能描述:RM, RM/I, RM/ILP cores and |
| RM4-3H3 | 制造商:FERROXCUBE 制造商全稱:Ferroxcube International Holding B.V. 功能描述:RM, RM/I, RM/ILP cores and |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。