參數(shù)資料
型號(hào)： L6917BD
廠商： STMICROELECTRONICS
元件分類： 穩(wěn)壓器
英文描述： SWITCHING CONTROLLER, 600 kHz SWITCHING FREQ-MAX, PDSO28
封裝： SO-28
文件頁(yè)數(shù)： 33/33頁(yè)
文件大小： 631K
代理商： L6917BD
Obsolete
Product(s)
- Obsolete
Product(s)
9/33
L6917B
Digital to Analog Converter
The built-in digital to analog converter allows the adjustment of the output voltage from 1.100V to 1.850V with
25mV as shown in the previous table 1. The internal reference is trimmed to ensure the precision of 0.8% and
a zero temperature coefficient around 70°C. The internal reference voltage for the regulation is programmed by
the voltage identification (VID) pins. These are TTL compatible inputs of an internal DAC that is realized by
means of a series of resistors providing a partition of the internal voltage reference. The VID code drives a mul-
tiplexer that selects a voltage on a precise point of the divider. The DAC output is delivered to an amplifier ob-
taining the VPROG voltage reference (i.e. the set-point of the error amplifier). Internal pull-ups are provided
(realized with a 5
A current generator up to 3.3V max); in this way, to program a logic "1" it is enough to leave
the pin floating, while to program a logic "0" it is enough to short the pin to GND. VID code “11111” programs
the NOCPU state: all mosfets are turned OFF and the condition is latched.
The voltage identification (VID) pin configuration also sets the power-good thresholds (PGOOD) and the over-
voltage protection (OVP) thresholds.
Soft Start and INHIBIT
At start-up a ramp is generated increasing the loop reference from 0V to the final value programmed by VID in
2048 clock periods as shown in figure 2.
Before soft start, the lower power MOS are turned ON after that VCCDR reaches 2V (independently by Vcc value)
to discharge the output capacitor and to protect the load from high side mosfet failures. Once soft start begins,
the reference is increased; when it reaches the bottom of the oscillator triangular waveform (1V typ) also the
upper MOS begins to switch and the output voltage starts to increase with closed loop regulation.. At the end of
the digital soft start, the Power Good comparator is enabled and the PGOOD signal is then driven high (See fig.
2). The Under Voltage comparator enabled when the reference voltage reaches 0.8V.
The Soft-Start will not take place, if both VCC and VCCDR pins are not above their own turn-on thresholds. Dur-
ing normal operation, if any under-voltage is detected on one of the two supplies the device shuts down.
Forcing the OSC/INH/FAULT pin to a voltage lower than 0.8V the device enter in INHIBIT mode: all the power
mosfets are turned off until this condition is removed. When this pin is freed, the OSC/INH/FAULT pin reaches
the band-gap voltage and the soft start begins.
Figure 2. Soft Start
VIN=VCCDR
VLGATEx
PGOOD
VOUT
t
2V
Turn ON threshold
2048 Clock Cycles
Timing Diagram
Acquisition:
CH1 = PGOOD; CH2 = VOUT; CH4 = LGATEx
相關(guān)PDF資料
PDF描述
L6917BDTR SWITCHING CONTROLLER, 600 kHz SWITCHING FREQ-MAX, PDSO28
L6917D SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO28
L6918ADTR SWITCHING CONTROLLER, 1200 kHz SWITCHING FREQ-MAX, PDSO28
L6918AD SWITCHING CONTROLLER, 1200 kHz SWITCHING FREQ-MAX, PDSO28
L6919CD SWITCHING CONTROLLER, 200 kHz SWITCHING FREQ-MAX, PDSO28
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L6917BDTR 功能描述:DC/DC 開關(guān)控制器 Prog Dual-Phase Cont RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
L6917D 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC
L6917DTR 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC
L6918 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:5 BIT PROGRAMMABLE MULTIPHASE CONTROLLER
L6918A 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:5 BIT PROGRAMMABLE MULTIPHASE CONTROLLER
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