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參數(shù)資料
| 型號： | ML4830 |
| 廠商： | Fairchild Semiconductor Corporation |
| 英文描述： | Electronic Ballast Controller(電子整流器控制器) |
| 中文描述： | 電子鎮(zhèn)流器控制器（電子整流器控制器） |
| 文件頁數(shù)： | 8/15頁 |
| 文件大?。?/td> | 134K |
| 代理商： | ML4830 |
ML4830
8
REV. 1.0 10/12/2000
IC BIAS, UNDER-VOLTAGE LOCKOUT AND THERMAL
SHUTDOWN
The IC includes a shunt regulator which will limit the
voltage at VCC to 13.5 (V
CCZ
). The IC should be fed with
a current limited source, typically derived from the ballast
transformer auxiliary winding. When VCC is below V
CCZ
– 0.7V, the IC draws less than 1.7mA of quiescent current
and the outputs are off. This allows the IC to start using a
“bleed resistor” from the rectified AC line.
VCCZ
V(ON)
V
CC
I
CC
t
V(OFF)
15mA
1.3mA
t
Figure 3. Typical V
CC
and I
CC
waveforms when ML4830
is started with a bleed resistor from the rectified AC line
and bootstrapped from the ballast transformer.
To help reduce ballast cost, the ML4830 includes a
temperature sensor which will inhibit ballast operation if
the IC’s junction temperature exceeds 120°C. In order to
use this sensor in lieu of an external sensor, care should be
taken when placing the IC to ensure that it is sensing
temperature at the physically appropriate point in the
ballast. The ML4830’s die temperature can be estimated
with the following equation:
T
T
P
C W
°
/
J
A
D
×
×
65
(7)
STARTING, RE-START, PREHEAT AND INTERRUPT
The lamp starting scenario implemented in the ML4830 is
designed to maximize lamp life and minimize ballast
heating during lamp out conditions.
The circuit in Figure 4 controls the lamp starting scenarios:
Filament preheat and Lamp Out interrupt. C(X) is charged
withacurrent ofI
or0 625
(
anddisch
ed
R SET
(
4
)
)
arg
through R(X). The voltage at C(X) is initialized to 0.7V
(V
BE
) at power up. The time for C(X) to rise to 3.4V is the
filament preheat time. During that time, the oscillator
ch
ing current I
isR2 5
(
inbothVCO
es
CHG
arg
(
)
)
mod .
This will produce a high frequency (or low duty cycle) for
filament preheat, but will not produce sufficient voltage to
ignite the lamp.
After cathode heating, the inverter frequency drops to
F
MIN
causing a high voltage to appear to ignite the lamp.
If the voltage does not drop when the lamp is supposed to
have ignited, the lamp voltage feedback coming into Pin
10 rises to above V
REF
, the C(X) charging current is shut off
and the inverter is inhibited until C(X) is discharged by
R(X) to the 1.2V threshold. Shutting off the inverter in this
manner prevents the inverter from generating excessive
heat when the lamp fails to strike or is out of socket.
Typically this time is set to be fairly long by choosing a
large value of R(X).
LFB OUT is ignored until C(X) reaches 6.8V threshold.
The lamps are therefore driven to full power and then
dimmed. The C(X) pin is clamped to about 7.5V.
A timing diagram of lamp ignition and restart sequences
provided by the circuit of Figure 4 is given in Figure 7.
12
10
R(X)
C(X)
6.8
+
–
1.2/3.4
HEAT
INHIBIT
.625
R(SET)
+
–
1.2/6.8
–
+
V
REF
DIMMING
LOCKOUT
R(X)/C(X)
INT
Q
R
S
Figure 4. Lamp Preheat and Interrupt Timers
Mode
PWM
FM
[F(MAX) to F(MIN)]
2
Preheat
50%
Dimming
Lock-out
D(MAX)%
F(MIN)
Dimming
Control
0 to D(MAX)%
F(MIN) to F(MAX)
Figure 5. Lamp Starting Summary
A summary of the lamp starting scenarios are given in
figure 5 for both PWM and Frequency Modulation modes.
The PWM duty cycle is defined as:
Duty Cycle
t
t
ON
CLK
=
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| ML4830CP | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:Electronic Ballast Controller |
| ML4830CS | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:Electronic Ballast Controller |
| ML4831 | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:Electronic Ballast Controller |
| ML483-1 | 制造商:CLARKE INTERNATIONAL 功能描述:CASTOR 136KG 4" SWIVEL/BRAK 制造商:CLARKE INTERNATIONAL 功能描述:CASTOR, 136KG, 4", SWIVEL/BRAKE, PLASTIC 制造商:CLARKE INTERNATIONAL 功能描述:CASTOR, 136KG, 4", SWIVEL/BRAKE, PLASTIC, For Use With:Industrial and Material Handling Applications, Carrying Capacity:136kg, Wheel Diameter:100mm , RoHS Compliant: NA |
| ML4831CP | 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Fairchild Semiconductor Corporation 功能描述: |
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