參數(shù)資料
型號(hào): LTC3632IDD#TRPBF
廠商: LINEAR INTEGRATED SYSTEMS INC
元件分類: 穩(wěn)壓器
英文描述: 0.06 A SWITCHING REGULATOR, PDSO8
封裝: 3 X 3 MM, LEAD FREE, PLASTIC, MO-229WEED-1, DFN-8
文件頁(yè)數(shù): 19/20頁(yè)
文件大?。?/td> 247K
代理商: LTC3632IDD#TRPBF
LTC3632
8
3632f
OPERATION
The LTC3632 is a step-down DC/DC converter with internal
power switches that uses Burst Mode control, combin-
ing low quiescent current with high switching frequency,
which results in high efciency across a wide range of
load currents. Burst Mode operation functions by using
short “burst” cycles to ramp the inductor current through
the internal power switches, followed by a sleep cycle
where the power switches are off and the load current is
supplied by the output capacitor. During the sleep cycle,
the LTC3632 draws only 12μA of supply current. At light
loads, the burst cycles are a small percentage of the total
cycle time which minimizes the average supply current,
greatly improving efciency.
Main Control Loop
The feedback comparator monitors the voltage on the VFB
pin and compares it to an internal 800mV reference. If
this voltage is greater than the reference, the comparator
activates a sleep mode in which the power switches and
current comparators are disabled, reducing the VIN pin
supply current to only 12μA. As the load current discharges
the output capacitor, the voltage on the VFB pin decreases.
When this voltage falls 5mV below the 800mV reference,
the feedback comparator trips and enables burst cycles.
At the beginning of the burst cycle, the internal high side
power switch (P-channel MOSFET) is turned on and the
inductor current begins to ramp up. The inductor current
increases until either the current exceeds the peak current
comparator threshold or the voltage on the VFB pin exceeds
800mV, at which time the high side power switch is turned
off. The low side power switch (N-channel MOSFET) is
then turned on. The inductor current ramps down until
the reverse current comparator trips, signaling that the
current is close to zero. If the voltage on the VFB pin is
still less than the 800mV reference, the high side power
switch is turned on again and another cycle commences.
The average current during a burst cycle will normally be
greater than the average load current. For this architecture,
the maximum average output current is equal to half of
the peak current.
The hysteretic nature of this control architecture results
in a switching frequency that is a function of the input
voltage, output voltage and inductor value. This behavior
provides inherent short-circuit protection. If the output
is shorted to ground, the inductor current will decay very
slowly during a single switching cycle. Since the high side
switch turns on only when the inductor current is near
zero, the LTC3632 inherently switches at a lower frequency
during start-up or short-circuit conditions.
Start-Up and Shutdown
If the voltage on the RUN pin is less than 0.7V, the LTC3632
enters a shutdown mode in which all internal circuitry is
disabled, reducing the DC supply current to 3μA. When the
voltage on the RUN pin exceeds 1.2V, normal operation of
the main control loop is enabled. The RUN pin comparator
has 110mV of internal hysteresis, and therefore must fall
below 1.1V to disable the main control loop.
The HYST pin provides an added degree of exibility for
the RUN pin operation. This open-drain output is pulled
to ground whenever the RUN comparator is not tripped,
signaling that the LTC3632 is not in normal operation. In
applications where the RUN pin is used to monitor the
VIN voltage through an external resistive divider, the HYST
pin can be used to increase the effective RUN comparator
hysteresis.
An internal 1ms soft-start function limits the ramp rate of
the output voltage on start-up to prevent excessive input
supply droop. If a longer ramp time and consequently less
supply droop is desired, a capacitor can be placed from the
SS pin to ground. The 5μA current that is sourced out of
this pin will create a smooth voltage ramp on the capacitor.
If this ramp rate is slower than the internal 1ms soft-start,
then the output voltage will be limited by the ramp rate
(Refer to Block Diagram)
相關(guān)PDF資料
PDF描述
LTC3632EDD#PBF 0.06 A SWITCHING REGULATOR, PDSO8
LTC3633EUFD#TRPBF SWITCHING REGULATOR, PQCC28
LTC3634EUFD#PBF 5.5 A DUAL SWITCHING CONTROLLER, 4600 kHz SWITCHING FREQ-MAX, PQCC28
LTC3634EFE#TRPBF 5.5 A DUAL SWITCHING CONTROLLER, 4600 kHz SWITCHING FREQ-MAX, PDSO28
LTC3634EFE#PBF 5.5 A DUAL SWITCHING CONTROLLER, 4600 kHz SWITCHING FREQ-MAX, PDSO28
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC3632IMS8E#PBF 功能描述:IC REG BUCK SYNC ADJ 20MA 8MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V,1.5V,1.8V,2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開(kāi)關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP,10-MSOP(0.118",3.00mm 寬)裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤
LTC3632IMS8E#TRPBF 功能描述:IC REG BUCK SYNC ADJ 20MA 8MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V,1.5V,1.8V,2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開(kāi)關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP,10-MSOP(0.118",3.00mm 寬)裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤
LTC3633AEFE#PBF 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 3.6V to 20V 28-Pin TSSOP EP 制造商:Linear Technology 功能描述:IC REG BUCK ADJ 3A DL 28TSSOP 制造商:Linear Technology 功能描述:BUCK DUAL 3.6-20V 4MHZ 3A 28TSSOP 制造商:Linear Technology 功能描述:BUCK, DUAL, 3.6-20V, 4MHZ, 3A, 28TSSOP 制造商:Linear Technology 功能描述:DP-SWREG/Monolithic, Dual 3A, 20Vin, 4MHz, Monolithic Synchronous Step-Down Regu 制造商:Linear Technology 功能描述:DC-DC CONVERTER, BUCK, 4MHZ, TSSOP-28, Primary Input Voltage:15V, No. of Outputs:2, Output Current:3A, No. of Pins:28, Operating Temperature Min:-40C, Operating Temperature Max:125C, MSL:MSL 1 - Unlimited, Package / Case:28-TSSOP , RoHS Compliant: Yes
LTC3633AEFE#TRPBF 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 3.6V to 20V 28-Pin TSSOP EP T/R 制造商:Linear Technology 功能描述:IC REG BUCK ADJ 3A DL 28TSSOP
LTC3633AEFE-1#PBF 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 3.6V to 20V 28-Pin TSSOP EP 制造商:Linear Technology 功能描述:IC REG BUCK ADJ 3A DL 28TSSOP 制造商:Linear Technology 功能描述:BUCK DUAL 3.6-20V 4MHZ 3A 28TSSOP 制造商:Linear Technology 功能描述:BUCK, DUAL, 3.6-20V, 4MHZ, 3A, 28TSSOP 制造商:Linear Technology 功能描述:DP-SWREG/Monolithic, Dual 3A, 20Vin, 4MHz, Monolithic Synchronous Step-Down Regu 制造商:Linear Technology 功能描述:DC-DC CONVERTER, BUCK, 4MHZ, TSSOP-28, Primary Input Voltage:15V, No. of Outputs:2, Output Current:3A, No. of Pins:28, Operating Temperature Min:-40C, Operating Temperature Max:125C, MSL:MSL 1 - Unlimited, Package / Case:28-TSSOP , RoHS Compliant: Yes