參數(shù)資料
型號： PM6685TR
廠商： STMICROELECTRONICS
元件分類： 穩(wěn)壓器
英文描述： DUAL SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, QCC32
封裝： 5 X 5 MM, 1 MM HEIGHT, 0.50 MM PITCH, LEAD FREE, VFQFPN-32
文件頁數(shù)： 13/52頁
文件大?。?/td> 2536K
代理商： PM6685TR
Device description
PM6685
20/52
7
Device description
The PM6685 is a dual step-down controller dedicated to provide logic voltages for notebook
computers.
It is based on a Constant On Time control architecture. This type of control offers a very fast
load transient response with a minimum external component count. A typical application
circuit is shown in Figure 27 on page 19. The PM6685 regulates two fixed output voltages:
5V and 3.3V. The switching frequency of the two sections can be adjusted to approximately
200/300kHz, 300/400kHz or 400/500kHz respectively. In order to maximize the efficiency at
light load condition, a pulse skipping mode can be selected. The PM6685 includes also two
linear regulators (LDO5 and LDO3) that allow the shutdown of the respective switching
sections in low consumption status. On the other hand, to maximize the efficiency in higher
consumption status, the linear regulators can be turned off and their outputs can be
supplied directly from the switching outputs. The PM6685 provides protection versus
overvoltage, undervoltage and overtemperature as well as power good signals for
monitoring purposes. An external 1.237V reference is available.
7.1
Constant on time PWM control
If the SKIP pin is tied to 5V, the device works in PWM mode. Each power section has an
independent on time control.The PM6685 implements a pseudo-fixed switching frequency,
Constant On Time (COT) controller as core of the switched mode section. Each power
section has an independent COT control.
The COT controller is based on a relatively simple algorithm and uses the ripple voltage due
to the output capacitor’s ESR to trigger the fixed on-time one-shot generator. In this way, the
output capacitor’s ESR acts as a current sense resistor providing the appropriate ramp
signal to the PWM comparator. On-time one-shot duration is directly proportional to the
output voltage VOUT, sensed at the OUT5/OUT3 pins, and inversely proportional to the
input voltage VIN, sensed at the VIN pin, as follows:
Equation 1
This leads to a nearly constant switching frequency, regardless of input and output voltages.
When the output voltage goes lower than the regulated voltage Vreg, the on-time one shot
generator directly drives the high side MOSFET for a fixed on time allowing the inductor
current to increase; after the on time, an off time phase, in which the low side MOSFET is
turned on, follows. Figure 28 on page 21 shows the inductor current and the output voltage
waveforms in PWM mode.
IN
OUT
ON
V
K
T
×
=
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
PM6686 制造商:STMicroelectronics 功能描述:
PM6686TR 功能描述:DC/DC 開關(guān)控制器 Step-down Controller w/adj. voltages-dual 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
PM6-6F-L 功能描述:端子 Metric Fork Terminal non-insulated, 4.0 RoHS:否 制造商:AVX 產(chǎn)品:Junction Box - Wire to Wire 系列:9826 線規(guī):26-18 接線柱/接頭大小: 絕緣: 顏色:Red 型式:Female 觸點電鍍:Tin over Nickel 觸點材料:Beryllium Copper, Phosphor Bronze 端接類型:Crimp
PM6-6R-D 制造商:Panduit Corp 功能描述:
PM6-6R-L 功能描述:端子 Metric Ring Terminal non-insulated, 2.5 RoHS:否 制造商:AVX 產(chǎn)品:Junction Box - Wire to Wire 系列:9826 線規(guī):26-18 接線柱/接頭大小: 絕緣: 顏色:Red 型式:Female 觸點電鍍:Tin over Nickel 觸點材料:Beryllium Copper, Phosphor Bronze 端接類型:Crimp
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