- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄379479 > UCC2976TRPW (Texas Instruments, Inc.) BALLAST/BACKLIGHT CONTROLLER/DRIVER|TSSOP|8PIN|PLASTIC PDF資料下載
參數(shù)資料
| 型號(hào)： | UCC2976TRPW |
| 廠商： | Texas Instruments, Inc. |
| 英文描述： | BALLAST/BACKLIGHT CONTROLLER/DRIVER|TSSOP|8PIN|PLASTIC |
| 中文描述： | 鎮(zhèn)流器/背光控制器/驅(qū)動(dòng)器| TSSOP封裝| 8引腳|塑料 |
| 文件頁數(shù)： | 25/28頁 |
| 文件大?。?/td> | 433K |
| 代理商： | UCC2976TRPW |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁當(dāng)前第25頁第26頁第27頁第28頁
SLUS499A
–
NOVEMBER 2001
–
REVISED JANUARY 2002
25
www.ti.com
APPLICATION INFORMATION
burst dimming with the OPEN/SD pin
A burst dimming technique can be used with CCFLs when a wide dimming range is required, this technique can
also yield better efficiency at light loads. Burst dimming is implemented by running the lamp at full current when
on, where the on/off duty factor is controlled a low frequency to provide dimming. In order to prevent visible
flicker, the burst frequency needs to be set higher than 80 Hz.
The UCC397x family is initially targeted for operating the PZT using analog dimming, however, burst dimming
can be implemented by controlling the OPEN/SD pin directly with a square wave. Figure 22 shows burst
dimming performance using the UCC3976 at 125 Hz and 50% duty cycle. In Figures 22
–
25, trace 1 is the drain
connection of the external P- and N-Channel MOSFETs, trace 2 is the OPEN/SD pin which is externally driven
with a 5-V square wave, trace 3 is the COMP pin which is used to lock the operating frequency and trace 4 is
the lamp voltage. These scope graphics were captured with a digital oscilloscope, so aliasing is present in
Figures 22
–
24. Referring back to Figure 22, when OPEN/SD is driven to 5 V the part is in shutdown and the
controller is disabled. When OPEN/SD is forced to 0 V by the external source the controller goes through its
startup sequence with COMP starting at 0 V allowing the PZT to strike the lamp and lock on the frequency
required to regulate the lamp at full current. The size of the feedback capacitor determines the slew rate at which
COMP can lock the system frequency which effects the achievable duty cycle of burst dimming. Fortunately,
the feedback cap with burst dimming can be smaller than with analog dimming since the system small signal
gain is lower at full lamp load. Figures 23 and 24 show burst dimming at approximately 10% and 90% duty cycle
respectively. Figure 25 shows a close up of the startup sequence when OPEN/SD is pulled low. COMP is
preconditioned to 0 V before switching begins and then allowed to ramp up. PZT secondary voltage ramps as
the frequency decreases until the lamp strikes and operates. Strike voltage for the lamp is barely detectable
since the lamp is warm and operating from the previous burst cycles.
VCOMP
VOPEN/SD
VLAMP
VOPEN/SD
Figure 22. UCC3976 Burst Dimming at 50% Duty Cycle
VIN = 12 Vdc
VLAMP = 600 V
fOSC = 125 Hz
50% Duty Cycle
ILAMP = 5 mA
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| UCC2977TRPW | Precision 500 mA regulators |
| UCC3976TRPW | Low consumption voltage and current controller for battery chargers and adaptors |
| UCC3977TRPW | BALLAST/BACKLIGHT CONTROLLER/DRIVER|TSSOP|8PIN|PLASTIC |
| UCC35705DGKTR | HIGH - SPEED VOLTAGE MODE PULSE MODE WIDTH MODULATOR |
| UCC35706DTR | HIGH - SPEED VOLTAGE MODE PULSE MODE WIDTH MODULATOR |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| UCC2977EVM | 功能描述:電源管理IC開發(fā)工具 UCC2977 Eval Mod RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| UCC2977PW | 功能描述:LCD 驅(qū)動(dòng)器 Multi-Topology Piezoelectric RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時(shí)鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
| UCC2977PWG4 | 功能描述:LCD 驅(qū)動(dòng)器 Multi-Topology Piezoelectric RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時(shí)鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
| UCC2977PWR | 功能描述:LCD 驅(qū)動(dòng)器 Multi-Topology Piezoelectric RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時(shí)鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
| UCC2977PWRG4 | 功能描述:LCD 驅(qū)動(dòng)器 Multi-Topology Piezoelectric RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時(shí)鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。