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부품번호 | L4916 기능 |
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기능 | VOLTAGE REGULATOR PLUS FILTER | ||
제조업체 | STMicroelectronics | ||
로고 | |||
전체 8 페이지수
® L4916
VOLTAGE REGULATOR PLUS FILTER
........ FIXEDOUTPUT VOLTAGE8.5 V
250 mA OUTPUT CURRENT
HIGH RIPPLE REJECTION
HIGH LOAD REGULATION
HIGH LINE REGULATION
SHORT CIRCUIT PROTECTION
THERMAL SHUT DOWN WITH HYSTERESIS
DUMP PROTECTION
DESCRIPTION
This circuit combinesboth a filter and a voltageregu-
lator in order to provide a high ripple rejection over a
wider input voltage range.
A supervisor low-pass loop of the element prevents
the outputtransistor from saturationat low input volt-
ages.
The non linear behaviour of this control circuitry
allows a fast settling of the filter.
BLOCK DIAGRAM
POWER MINIDIP
(4 + 4)
ORDERING NUMBER : L4916
June 2000
1/8
L4916
Figure 2 : P.C. Board and Component Layout of Fig. 1 (1 : 1 scale).
PRINCIPLE OF OPERATION
During normal operation (input voltage upper than
VI MIN = VOUT NOM + ∆VI/O). The device works as a
normal voltage regulatorbuilt aroundthe OP1 of the
block diagram.
The series pass element use a PNP-NPN connec-
tion to reduce the dropout. The reference voltage of
the OP1 is derived from a REF throughthe OP2and
Q3, acting as an active zener diode of value VREF.
In this conditionthe device works in the range (1) of
the characteristic of the non linear drop control unit
(see fig.3).
The output voltage is fixed to its nominal value:
VOUT NOM = VREF (1 + R1 ) =
R2
VCFT (1 + R1 )
R2
R1
= INTERNALLY FIXED RATIO = 2.4
R2
The ripple rejection is quite high (70 dB) and inde-
pendent from CFT value.
On the usualvoltage regulators, when the input vol-
tage goes below the nominal value, the regulation
transistors (series element) saturate bringing the
system out of regulation making it very sensible to
every variation of the input voltage. On the contrary,
a control loop on the L4916 consents to avoid the
saturation of the series element by regulating the
value of the reference voltage (pin 2). In fact, when-
ever the input voltage decreases below VI MIN the
supervisor loop, utilizing a non linear OTA, forces
the reference voltage at pin 2 to decrease by dis-
charging CFT. So, during the static mode, when the
input voltage goes below VMIN the drop out is kept
fixed to about 1.6V. In this condition the device
works as a low pass filter in the range (2) of the OTA
characteristic. The ripple rejection is externally ad-
justable acting on CFT as follows :
SVR (jw) = VI (jw) =
Vout (jw)
1 + 10-6
gm R1
(1 + )
Where:
jwCFT
R2
gm = 2 . 10-5 Ω-1 = OTA’S typical transconductance
value on linear region
R1
= fixed ratio
R2
CFT = value of capacitor in µF
The reaction time of the supervisor loop is given by
the transconductanceof the OTA and by CFT. When
the value of the ripple voltage is so high and its ne-
gative peak is fast enough to determine an istanta-
neous decrease of the dropout till 1.2 V, the OTA
works in a higher transconductance condition
[range (3) of the characteristic] and discharge the
capacitor rapidously.
If the ripple frequency is high enough the capacitor
won’t charge itself completely, and the output volt-
age reachesa small value allowinga betterripple re-
jection ; the device’s again working as a filter (fast
transient range).
With CFT = 10 µF; f = 100Hz a SVR of 35 is obtained.
4/8
4페이지 DIM.
mm
inch
MIN. TYP. MAX. MIN. TYP. MAX.
A 3.3
0.130
a1 0.7
0.028
B 1.39
1.65 0.055
0.065
B1 0.91
1.04 0.036
0.041
b 0.5
0.020
b1 0.38
0.5 0.015
0.020
D 9.8 0.386
E 8.8
0.346
e 2.54
0.100
e3 7.62
0.300
e4 7.62
0.300
F 7.1 0.280
I 4.8 0.189
L 3.3
0.130
Z 0.44
1.6 0.017
0.063
L4916
OUTLINE AND
MECHANICAL DATA
PowerMinidip
7/8
7페이지 | |||
구 성 | 총 8 페이지수 | ||
다운로드 | [ L4916.PDF 데이터시트 ] |
당사 플랫폼은 키워드, 제품 이름 또는 부품 번호를 사용하여 검색할 수 있는 |
구매 문의 | 일반 IC 문의 : 샘플 및 소량 구매 ----------------------------------------------------------------------- IGBT, TR 모듈, SCR 및 다이오드 모듈을 포함한 광범위한 전력 반도체를 판매합니다. 전력 반도체 전문업체 상호 : 아이지 인터내셔날 사이트 방문 : [ 홈페이지 ] [ 블로그 1 ] [ 블로그 2 ] |
부품번호 | 상세설명 및 기능 | 제조사 |
L4915 | ADJUSTABLE VOLTAGE REGULATOR PLUS FILTER | STMicroelectronics |
L4916 | VOLTAGE REGULATOR PLUS FILTER | STMicroelectronics |
DataSheet.kr | 2020 | 연락처 | 링크모음 | 검색 | 사이트맵 |