參數(shù)資料
型號: PM6670ASTR
廠商: STMICROELECTRONICS
元件分類: 穩(wěn)壓器
英文描述: 3 A SWITCHING CONTROLLER, QCC24
封裝: 4 X 4 MM, LEAD FREE, VFQFPN-24
文件頁數(shù): 13/53頁
文件大?。?/td> 745K
代理商: PM6670ASTR
Device description
PM6670AS
20/53
Doc ID 14436 Rev 2
7.1
VDDQ section - constant on-time PWM controller
The PM6670AS uses a pseudo-fixed frequency, constant on-time (COT) controller as the
core of the switching section. It is well known that the COT controller uses a relatively simple
algorithm and uses the ripple voltage derived across the output capacitor’s ESR to trigger
the 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. Nearly
constant switching frequency is achieved by the system’s loop in steady-state operating
conditions by varying the on-time duration, avoiding thus the need for a clock generator. The
on-time one shot duration is directly proportional to the output voltage, sensed at VSNS pin,
and inversely proportional to the input voltage, sensed at the VOSC pin, as follows:
Equation 1
where KOSC is a constant value (130ns typ.) and τ is the internal propagation delay
(40 ns typ.). The one-shot generator directly drives the high-side MOSFET at the beginning
of each switching cycle allowing the inductor current to increase; after the on-time has
expired, an off-time phase, in which the low-side MOSFET is turned on, follows. The off-time
duration is solely determined by the output voltage: when lower than the set value (i.e. the
voltage at VSNS pin is lower than the internal reference VR = 0.9 V), the synchronous
rectifier is turned off and a new cycle begins (Figure 26).
Figure 26.
Inductor current and output voltage in steady state conditions
τ
+
=
OSC
SNS
OSC
ON
V
K
T
Ton
Toff
Inductor
current
t
Output
voltage
Vreg
Ton
Toff
Inductor
current
t
Output
voltage
Vreg
相關(guān)PDF資料
PDF描述
PM6670AS 3 A SWITCHING CONTROLLER, QCC24
PM6670A 1.4 A SWITCHING CONTROLLER, QCC24
PM6670STR 3 A SWITCHING CONTROLLER, QCC24
PM6670S 3 A SWITCHING CONTROLLER, QCC24
PM6670TR 1.4 A SWITCHING CONTROLLER, QCC24
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
PM6670ATR 功能描述:直流/直流開關(guān)調(diào)節(jié)器 Complete DDR2/3 Mem Pwr supply controllr RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
PM6670S 功能描述:DC/DC 開關(guān)控制器 DDR 2/3 Memory Pwr Cntrl 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 安裝風格: 封裝 / 箱體:CPAK
PM6670STR 功能描述:DC/DC 開關(guān)控制器 Complete DDR2/3 Mem Pwr supply controllr 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 安裝風格: 封裝 / 箱體:CPAK
PM6670TR 功能描述:直流/直流開關(guān)調(diào)節(jié)器 Complete DDR2/3 Mem Pwr supply controllr RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
PM6675 制造商:STMicroelectronics 功能描述: 制造商:STMicroelectronics 功能描述:LDO CNTRLR STDN 0.6V TO 3.3V/1.5V 24PIN VFQFPN - Rail/Tube