參數(shù)資料
型號(hào)： MC34701EK
廠商： 飛思卡爾半導(dǎo)體(中國(guó))有限公司
英文描述： 1.5 A Switch-Mode Power Supply with Linear Regulator
中文描述： 1.5開關(guān)模式電源，線性穩(wěn)壓器
文件頁(yè)數(shù)： 18/38頁(yè)
文件大?。?/td> 739K
代理商： MC34701EK
Analog Integrated Circuit Device Data
Freescale Semiconductor
18
34701
FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
Figure 12. Boost Regulator Startup (Not To Scale)
SWITCHING REGULATOR
The switching regulator is a high-frequency (300 kHz
default, adjustable in the range from 200 kHz to 400 kHz),
synchronous buck converter driving integrated high-side and
low-side N-channel power MOSFETs. The switching
regulator output voltage is adjustable by means of an external
resistor divider to provide the required output voltage within
±2.0% accuracy, and is intended to directly power the core of
the microprocessor. The buck controller uses a PWM Voltage
Mode Control topology with Feed-Forward to achieve
excellent line and load regulation.
The 34702 integrated boost regulator provides a
7.75
V
rail which is used to properly bias the switcher’s MOSFET. In
addition, the boost structure has a very low start up voltage
(Typically 1.6 V), hence ensuring very low input voltage
functionality. A typical bootstrap technique is used to provide
voltage necessary to properly enhance the high-side
MOSFET gate. When the regulator is supplied only from low-
input voltage (e.g., single +3.3 V supply rail), the bootstrap
capacitor is charged from the internal boost regulator output
V
BST
through an external diode. This arrangement allows
the 34701 to operate from very low input voltage and also
comply with the power sequencing requirements of the
supplied microcontroller.
Figure 13. Switching Regulator Current Limit
(Not To Scale)
To avoid destruction of the supplied circuits, the switching
regulator has a current limit with retry capability. When an
overcurrent condition occurs and the switch current reaches
the peak current limit value, the main (high-side) switch is
turned off until the inductor current decays to the valley value,
which is one-half of the peak current limit. If an overcurrent
condition exists for 10 ms, the buck regulator control circuit
shuts the switcher OFF and the switcher retry timer starts to
time out. When the timer expires after 100 ms, the switcher
engages the start-up sequence and runs for 10 ms,
repeatedly checking for the overcurrent condition.
Figure 13
describes the switching regulator overcurrent condition and
current limit. During the current limited operation (e.g., in
case of short circuit on the switching regulator output), the
switching regulator operation is not synchronized to the
oscillator frequency.
Figure 14
(respectively
Figure 15
)
depicts the current limit with a retry capability feature of the
switcher (respectively LDO).
Figure 14. Switching Converter Overcurrent Protection
6.0 V
7.75V
Ipk= 1A typ.
0.6 A typ.
0.2 Atyp.
0.1 A typ.
Booster Output Voltage
0 V
Booster Inductor Current
Ipk
0.5 Ipk
tFAULT= 10 ms
Current Limit
Ipk
0.5 Ipk
tFAULT= 10 ms
0 A
tRet= 100 ms
Fault Timer
Retry Timer
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC34701EKR2 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 QUICCSUPPLY1 RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
MC34702EK 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 QUICCSUPPLY2 RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
MC34702EKR2 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 QUICCSUPPLY2 RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
MC34703 制造商:SPC Multicomp 功能描述:HEADER R/ANGLE 7WAY 制造商:SPC Multicomp 功能描述:HEADER, R/ANGLE, 7WAY
MC34703PNB 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 QUICC SUPPLY 3 RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
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