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參數(shù)資料
| 型號： | KA7540D |
| 廠商： | SAMSUNG SEMICONDUCTOR CO. LTD. |
| 英文描述： | Simple Dimming Ballast Control IC |
| 中文描述： | 簡單的調光鎮(zhèn)流器控制IC |
| 文件頁數(shù)： | 9/14頁 |
| 文件大?。?/td> | 104K |
| 代理商： | KA7540D |
KA7540
9
Dimming Control
The lighting output of the lamp can be controlled by varying the switching frequency of the ballast circuit. In voltage source
series resonant type converter, the output power is inversely proportional to the switching frequency. As a result, in order to
make the lamp lighting output less bright (so called “dimming”), the switching frequency should be increased compared to that
of the normal full lighting output frequency.
With KA7540, the switching frequency can be controlled by the voltage level at the pin #3 (Vdim). Since the IC starts to
operate, the voltage level at the dimming pin doesn’t affect the oscillator frequency until the time of td1 in figure 3. At the time
td1, the switching frequency starts to ramp up to the dimming switching frequency level that is determined by the voltage level
at the pin #3 (Vdim). In dimming mode, the timing capacitor charging current is increased by the following amount of the
dimming current (Id).
Id = 25uA
×
(Vref - Vd) / Vref
Vd = Vdim / 5
So, the equations for the dimming frequency are as following.
dt
If the dimming pin is open, the dimming pin voltage becomes 10V due to the internal 100
μ
A current source, which is
equivalent to the normal full lighting output case.
Dimming Control can be reallized by simple voltage source and current source of variable resistor at pin #3.
-------
----------------+
Ct
=
dTch dim
)
-------------------------------–
50uA
)
+
-----------------------------------------------------------------------
=
dTdis dim
)
-------------------------------–
7
50uA
×
)
Vref
+
---------------------------------------------------------------------------------
=
Ts dim
)
2
Tch dim
)
Tdis dim
)
+
(
)
×
=
fSW dim
)
Ts dim
)
---------------------
=
相關PDF資料 |
PDF描述 |
|---|---|
| KA7541 | Simple Ballast Controller |
| KA7541D | Simple Ballast Controller |
| KA75420Z | Voltage Detector |
| KA75290M | Voltage Detector |
| KA75290Z | Voltage Detector |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| KA7540DTF | 功能描述:開關變換器、穩(wěn)壓器與控制器 RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| KA7541 | 功能描述:開關變換器、穩(wěn)壓器與控制器 Ballast Controller Electronic RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| KA7541D | 功能描述:開關變換器、穩(wěn)壓器與控制器 Ballast Controller Electronic RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| KA7541DTF | 功能描述:開關變換器、穩(wěn)壓器與控制器 Ballast Controller Electronic RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| KA75420 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Voltage Detector |
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