- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄368518 > RM4190D883B (Raytheon Company) RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS PDF資料下載
參數(shù)資料
| 型號(hào)： | RM4190D883B |
| 廠商： | Raytheon Company |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| 中文描述： | 抗輻射高效，5安培開關(guān)穩(wěn)壓器 |
| 文件頁數(shù)： | 11/25頁 |
| 文件大?。?/td> | 174K |
| 代理商： | RM4190D883B |
RC4190
PRODUCT SPECIFICATION
11
Figure 13. Low Battery Detector
When the battery voltage drops below this threshold Q2 will
turn on and sink over 1500
μ
A typically. The low battery
detector circuitry may also be used for other, less conven-
tional applications (see Figures 19 and 20).
Automatic Shutdown
The bias control current for the reference is externally set by
a resistor from the I
C
pin to the battery. This current can vary
from 1.0
μ
A to 50
μ
A without affecting the operation of the
I
C
. Interrupting this current will disable the entire circuit,
causing the output voltage to go to 0V for step-down appli-
cations, and reducing the supply current to less than 1.0
μ
A.
Automatic shutdown of the RC4190 can be achieved using
the circuit of Figure 14.
Figure 14. Automatic Shutdown
A resistor is placed from the I
C
pin to ground, creating a
voltage divider. When the voltage at the I
C
pin is less than
1.2V, the RC4190 will begin to turn off. This scheme should
only be used in limited temperature range applications since
the “turn off” voltage at the I
C
pin has a temperature coeffi-
cient of -4.0 mV/
°
C. At 25
°
C, typically 250 nA is the mini-
mum current required by the I
C
pin to sustain operation.
A 5.0
μ
A voltage divider works well taking into account the
sustaining current of 250 nA and a threshold voltage of 0.4V
at turn off. As an example, if 3.0V is to be the turn off volt-
age, then R9 = 1.1/4.75
μ
A and R1 = (3.0 – 1.1) 5.0
μ
A or
about 240 k
and 390 k
respectively. The tempco at the
top of the divider will be -4.0 mV (R1 + R9)/R9 or
-10.5 mV/
°
C, an acceptable number for many applications.
+Vs
R4
R5
1
C2
V
1.31V
Q2
8
I
LBD
65-1651
LBR
LBD
65-2678
4190
+V
I
GND
3
6
5
R1
R9
V
BAT
S
C
Another method of automatic shutdown without temperature
limitations is the use of a zener diode in series with the I
C
pin and set resistor. When the battery voltage falls below V
Z
+ 1.2V the circuit will start to shut down. With this connec-
tion and the low battery detector, the application can be
designed to signal a display when the battery voltage has
dropped to the first programmed level, then shut itself off as
the battery reaches the zener threshold.
The set current can also be turned off by forcing the I
C
pin to
0.2V or less using an external transistor or mechanical
switch. An example of this is shown in Figure 15.
In this circuit an external control voltage is used to determine
the operating state of the RC4190. If the control voltage V
C
is a logic 1 at the input of the 4025 (CMOS Triple NOR
Gate), the voltage at the I
C
pin will be less than 0.5V forcing
the 4190 off (<0.1
μ
A I
CC
). Both the 2N3904 and 2N2907
will be off insuring long shelf for the battery since less than
1.0
μ
A is drawn by the circuit.
When V
C
goes to a logic 0, 2.0
μ
A is forced into the I
C
pin
through the 2.2 M
resistor and the NOR gate, and at the
same time the 2N3904 and 2N2907 turn on, connecting the
battery to the load.
As long as V
C
remains low the circuit will regulate the
output to 5.0V. This type of circuit is used to back up the
main supply voltage when line interruptions occur, a particu-
larly useful feature when using volatile memory systems.
9.0V Battery Life Extender
Figure 16 shows a common application: a circuit to extend
the lifetime of a 9.0V battery. The regulator remains in its
quiescent state (drawing only 215
μ
A) until the battery volt-
age decays below 7.5V, at which time it will start to switch
and regulate the output at 7.0V until the battery falls below
2.2V.
If this circuit operates at its typical efficiency of 80%, with
an output current of 10 mA, at 5.0V battery voltage, then the
average input current will be I
IN
= (V
OUT
x I
L
)
÷
(V
BAT
x
ef) or (7.0V x 10 mA)
÷
(5.0V x 0.8 mA) = 17.5 mA.
Bootstrapped Operation (Step-Up)
In step-up applications, power to the RC4190 can be derived
from the output voltage by connecting the +V
S
pin and the
top of R1 to the output voltage (Figure 17).
One requirement for this circuit is that the battery voltage
must be greater than 3.0V when it is energized or else there
will not be enough voltage at pin 5 to start up the I
C
. The big
advantage of this circuit is the ability to operate down to a
discharged battery voltage of 1.0V.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| RMB2S | MINIATURE GLASS PASSIVATED SINGLE-PHASE SURFACE MOUNT FAST RECOVERY BRIDGE RECTIFIER |
| RMB4S | MINIATURE GLASS PASSIVATED SINGLE-PHASE SURFACE MOUNT FAST RECOVERY BRIDGE RECTIFIER |
| RMDM-9PH1M-A174 | Micro-D Metal Shell - .050 Contact Spacing |
| RMDM-9SH1B1-A174 | Micro-D Metal Shell - .050 Contact Spacing |
| RMDM-9SH1B1-A30 | Micro-D Metal Shell - .050 Contact Spacing |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| RM4191D | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Voltage-Mode SMPS Controller |
| RM4191D/883B | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Voltage-Mode SMPS Controller |
| RM4192D | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Voltage-Mode SMPS Controller |
| RM4193JG | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC |
| RM4195K | 制造商:QP Semiconductor 功能描述:FROM FSC RM4195Z DIE TO-66 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。