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参数资料
| 型号： | DS3988T+T&R |
| 厂商： | Maxim Integrated |
| 文件页数： | 15/23页 |
| 文件大小： | 0K |
| 描述： | IC CCFL CNTRLR 8CH 48TQFP |
| 标准包装： | 2,000 |
| 类型： | CCFL 控制器 |
| 频率： | 40 ~ 80 kHz |
| 电流 - 电源： | 15mA |
| 电源电压： | 4.5 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 48-LQFP |
| 供应商设备封装： | 48-LQFP（7x7） |
| 包装： | 带卷 (TR) |
8-Channel Cold-Cathode
Fluorescent Lamp Controller
Figure 8 shows a flowchart of how the DS3988 controls
and monitors each lamp. The steps are as follows:
1) Supply Check—The lamps will not turn on unless the
DS3988 supply voltage is ≥ 4.5V and the voltage at
the supply voltage monitor (SVM) input is ≥ 2V.
2) Strike Lamp—When both the DS3988 and the DC
inverter supplies are above the minimum values, the
DS3988 will attempt to strike each enabled lamp for
768 lamp cycles [1 lamp cycle (seconds) = 1/lamp
frequency (Hertz)]. If the lamp doesn’t strike during
that time, the DS3988 will go into a fault-handling
stage (step 4). The DS3988 detects that the lamp
has struck by measuring the current flow through
the lamp. Also, if an overvoltage event is detected
during the strike attempt, the DS3988 will disable
the MOSFET gate drivers and go to the fault-han-
dling stage. If a lamp overcurrent is detected, the
DS3988 will immediately enter a Fault State.
3) Run Lamp—Once the lamp is struck, the DS3988
adjusts the MOSFET gate duty cycle to optimize the
lamp current. The lamp current sampling rate is user-
selectable with the LSR0 and LSR1 bits in CR2. If the
lamp current ever drops below the Open Lamp refer-
ence point for 256 lamp cycles, the lamp is consid-
ered extinguished. If this occurs or if an overvoltage
event is detected while the lamp is running, the
DS3988 will disable the MOSFET gate drivers and
go to the fault-handling stage. If a lamp overcurrent
is detected, the DS3988 will immediately enter a
Fault State.
4) Fault Handling—The DS3988 can be configured to
automatically restrike the lamp(s) in an attempt to
clear the detected fault condition (except for lamp
overcurrent faults). The automatic retry will make up
to 15 re-strike attempts before entering a Fault State.
Between each of the 15 retries, the controller will
wait 1024 lamp cycles. If after any of the retries the
fault has cleared, normal operation will resume. In
the case of a lamp overcurrent fault, the DS3988 will
skip the automatic retry even if it is enabled and will
immediately enter a Fault State.
FAULT-HANDLING STAGE 4
FAULT STATE
1
DEVICE AND INVERTER
SUPPLIES ABOVE
MINIMUM LEVEL?
[ACTIVATE FAULT OUTPUT]
YES
YES
NO
RESET FAULT COUNTER
AND FAULT OUTPUT
FAULT WAIT
[1024 LAMP CYCLES]
NO
FAULT COUNTER = 15?
YES
AUTORETRY ENABLED?
[ARD BIT AT CR1.5]
INCREMENT FAULT
COUNTER
2
FAULT
STRIKE LAMP
FAULT
LAMP STRIKE TIMEOUT
[LAMP OUT FOR 768
LAMP CYCLES]
FAULT
OVERVOLTAGE
[256 LAMP CYCLES]
LAMP STRIKES
LAMP
OVERCURRENT
[INSTANTANEOUS
FAULT
CORRECTLY
FAULT
LAMP EXTINGUISHED
RESPONSE IF ENABLED
WITH THE LOC BIT AT
CR1.0]
RUN LAMP
FAULT
[LAMP OUT FOR 256
LAMP CYCLES]
3
MOSFET GATE DRIVERS ENABLED
Figure 8. Fault-Handling Flow Chart
____________________________________________________________________
15
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS3991 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Low-Cost CCFL Controller |
| DS3991V | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Low-Cost CCFL Controller |
| DS3991VC | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Low-Cost CCFL Controller |
| DS3991VR | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Low-Cost CCFL Controller |
| DS3991VRC | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Low-Cost CCFL Controller |
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