- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄384457 > HV9903 (Supertex, Inc.) White LED Driver PDF資料下載
參數(shù)資料
| 型號(hào)： | HV9903 |
| 廠商： | Supertex, Inc. |
| 元件分類： | LED驅(qū)動(dòng)器 |
| 英文描述： | White LED Driver |
| 中文描述： | 白光LED驅(qū)動(dòng)器 |
| 文件頁(yè)數(shù)： | 6/12頁(yè) |
| 文件大小： | 326K |
| 代理商： | HV9903 |
lower standard value is 3.3
μ
H (10% tolerance) and
the corrected rating is then:
mA
359
μH
3
μH
7
mA
320
CORRECTED
I
Inductor data sheets may rate the inductor in terms of
DC current, RMS current, or saturation current. The
DC or saturation ratings should be used. Confirm that
the inductor is not saturating by observing the SW pin.
When an inductor saturates, current begins to climb
rapidly. This condition is evidenced by a breakpoint in
the SW voltage waveform as indicated in the diagram
below. Normally, the voltage at the SW pin should be
a fairly linear ramp, as the linear rise in inductor
current through the SW resistance produces a linear
voltage ramp. When the inductor saturates, the rapid
rise in current produces a likewise rapid rise in SW
voltage. Test using an HV9903 with a low switching
frequency.
SW Waveform Showing Inductor Saturation
Normal
Saturated
Gnd
Gnd
V
IN
Note: ringing or noise may be present.
Also, confirm that the driver is operating in
discontinuous mode by observing the voltage at the
SW pin while at minimum supply and maximum LED
current. For worst-case test purposes, select
components within their tolerance range as follows:
Inductor: high value
LED: high voltage drop
HV9903: high switching frequency
Some ringing in the SW waveform will be evident, but
is not a concern as the energy is very low. About 10-
15% idle time should be allowed to assure
discontinuous mode operation. Idle time is the
interval when there is no inductor current flowing, as
indicated when the SW voltage is at the supply
voltage level (with some ringing).
The following graphs show the SW waveform with
various inductor values and can assist in selecting an
inductor. The top graph shows an inductor value that
is acceptable, however, greater efficiency can be
achieved by increasing inductance. The bottom graph
shows continuous mode operation, which must be
avoided.
SW Waveform with Various Inductor Values
V
IN
Gnd
V
IN
Gnd
V
IN
Gnd
Inductance too low
Inductance ideal
Inductance too high
(continuous mode)
idle
Capacitor Selection
Proper selection of C
DD
and C
OUT
is essential to the
efficient operation of the LED driver. Both C
DD
and
C
OUT
should be around 1
μ
F with good high frequency
characteristics (low ESR and ESL). Ceramic
capacitors are a practical choice for their high
volumetric efficiency and good high frequency
characteristics, but pay attention to the capacitor’s
voltage coefficient. Some small, high value ceramic
capacitors can lose 75% of their capacitance at their
rated voltage! X5R, Y5V, and Z5U formulations are
more susceptible to this effect, as well as possessing
higher temperature coefficients. X7R formulations are
a better choice.
The voltage rating of C
DD
should be greater than the
maximum supply voltage. To be compatible with the
HV9903’s open LED protection, C
OUT
’s voltage rating
should be 35V or more.
HV9903
HV9903
6
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| HV9904 | HV9904 Multi Converter Controller |
| HV9904LG | HV9904 Multi Converter Controller |
| HV9904P | HV9904 Multi Converter Controller |
| HV9904X | HV9904 Multi Converter Controller |
| HV9906 | Simple Off-Line/PFC & >9V DC/DC Switcher |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| HV9903DB1 | 制造商:Supertex Inc 功能描述: |
| HV9903K6 | 功能描述:LED照明驅(qū)動(dòng)器 White LED Drvr RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N |
| HV9903K6-G | 功能描述:LED照明驅(qū)動(dòng)器 White LED Drvr RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N |
| HV9904 | 制造商:SUPERTEX 制造商全稱:SUPERTEX 功能描述:HV9904 Multi Converter Controller |
| HV9904LG | 功能描述:功率驅(qū)動(dòng)器IC HVCMOS D2 RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時(shí)間: 下降時(shí)間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。