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參數(shù)資料
| 型號(hào)： | ML4831 |
| 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(yè)數(shù)： | 8/14頁(yè) |
| 文件大小： | 165K |
| 代理商： | ML4831 |
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ML4831
8
The oscillator’s minimum frequency is set when I
CH
= 0
where:
F
R C
OSC
T
×
1
0 51
.
(5)
This assumes that t
CHG
>> t
DIS
.
When LFB OUT is high, I
CH
= 0 and the minimum
frequency occurs. The charging current varies according
to two control inputs to the oscillator:
1.
2.
The output of the preheat timer
The voltage at Pin 6 (lamp feedback amplifier
output)
In preheat condition, charging current is fixed at
I
R SET
(
CHG PREHEAT
(
)
.
)
=
2 5
(6)
In running mode, charging current decreases as the V
PIN6
rises from 0V to V
OH
of the LAMP FB amplifier. The
highest frequency will be attained when I
CHG
is highest,
which is attained when V
PIN6
is at 0V:
I
R SET
(
CHG( )
)
0
5
=
(7)
Highest lamp power, and lowest output frequency are
attained when V
PIN6
is at its maximum output voltage
(V
OH
).
In this condition, the minimum operating frequency of the
ballast is set per (5) above.
For the IC to be used effectively in dimming ballasts with
higher Q output networks a larger C
T
value and lower R
T
value can be used, to yield a smaller frequency excursion
over the control range (V
PIN6
). The discharge current is set
to 5mA. Assuming that I
DIS
>> I
RT
:
t
C
DIS VCO
(
T
)
×
490
(8)
IC BIAS, UNDER-VOLTAGE LOCKOUT AND THERMAL
SHUTDOWN
The IC includes a shunt regulator which will limit the
voltage at V
CC
to 13.5 (V
CCZ
). The IC should be fed with
a current limited source, typically derived from the ballast
transformer auxiliary winding. When V
CC
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.
To help reduce ballast cost, the ML4831 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 ML4831’s die temperature can be estimated
with the following equation:
T
T
P
C W
°
/
J
A
D
×
×
65
(9)
VCCZ
V(ON)
V(OFF)
15mA
1.3mA
V
CC
I
CC
t
t
Figure 6. Typical V
CC
and I
CC
Waveforms when
the ML4831 is Started with a Bleed Resistor from
the Rectified AC Line and Bootstrapped from an
Auxiliary Winding.
STARTING, RE-START, PREHEAT AND INTERRUPT
The lamp starting scenario implemented in the ML4831
is designed to maximize lamp life and minimize ballast
heating during lamp out conditions.
The circuit in Figure 7 controls the lamp starting scenarios:
Filament preheat and Lamp Out interrupt. C(X) is charged
with a current of I
R(SET)
/4 and discharged 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 charging current
(I
CHG
) is 2.5/R(SET). This will produce a high frequency
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 9 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).
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| 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: |
| ML483-1W | 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 |
| ML4832 | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:Electronic Dimming Ballast Controller |
| ML4832CP | 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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