データシートサーチシステム |
|
LM5001 データシート(PDF) 10 Page - Texas Instruments |
|
LM5001 データシート(HTML) 10 Page - Texas Instruments |
10 / 26 page PWM FB 5k COMP 5V VOUT LM5001 1 1 ¸¸ ¹ · ¨¨ © § 1 C1 C2 R2 RFEEDBACK R1 1.3V 1.26V FDC_POLE = FPOLE = FZERO = 2S x R1 x(C1 + C2) C1 xC2 2S x R2 xC2 2S x R2 x C1 + C2 LM5001, LM5001-Q1 SNVS484H – JANUARY 2007 – REVISED JULY 2015 www.ti.com Feature Description (continued) An external set-point resistor divider from VIN to GND can be used to determine the minimum operating input range of the regulator. The divider must be designed such that the EN pin exceeds the 1.26 V standby threshold when VIN is in the desired operating range. The internal 6 µA current source should be included when determining the resistor values. The shutdown and standby thresholds have 100 mV hysteresis to prevent noise from toggling between modes. When the VIN voltage is below 3.5 VDC during start-up and the operating temperature is below –20°C, the EN pin should have a pull-up resistor provides 2 µA or greater current. The EN pin is internally protected by a 6 V Zener diode through a 1 k Ω resistor. The enabling voltage may exceed the Zener voltage, however the Zener current should be limited to less than 4 mA. 7.3.5 Error Amplifier and PWM Comparator An internal high gain error amplifier generates an error signal proportional to the difference between the regulated output voltage and an internal precision reference. The output of the error amplifier is connected to the COMP pin allowing the user to add loop compensation, typically a Type II network, as illustrated in Figure 13. This network creates a low frequency pole that rolls off the high DC gain of the amplifier, which is necessary to accurately regulate the output voltage. FDC_POLE is the closed loop unity gain (0 dB) frequency of this pole. A zero provides phase boost near the closed loop unity gain frequency, and a high frequency pole attenuates switching noise. The PWM comparator compares the current sense signal from the current sense amplifier to the error amplifier output voltage at the COMP pin. Figure 13. Type II Compensator When isolation between primary and secondary circuits is required, the Error Amplifier is usually disabled by connecting the FB pin to GND. This allows the COMP pin to be driven directly by the collector of an opto-coupler. In isolated designs the external error amplifier is located on the secondary circuit and drives the opto-coupler LED. The compensation network is connected to the secondary side error amplifier. An example of an isolated regulator with an opto-coupler is shown in Figure 19. 7.3.6 Current Amplifier and Slope Compensation The LM5001 employs peak current mode control which also provides a cycle-by-cycle over current protection feature. An internal 50 m Ω current sense resistor measures the current in the power MOSFET source. The sense resistor voltage is amplified 30 times to provide a 1.5 V/A signal into the current limit comparator. Current limiting is initiated if the internal current limit comparator input exceeds the 1.5 V threshold, corresponding to 1 A. When the current limit comparator is triggered, the SW output pin immediately switches to a high impedance state. 10 Submit Documentation Feedback Copyright © 2007–2015, Texas Instruments Incorporated Product Folder Links: LM5001 LM5001-Q1 |
同様の部品番号 - LM5001_15 |
|
同様の説明 - LM5001_15 |
|
|
リンク URL |
プライバシーポリシー |
ALLDATASHEET.JP |
ALLDATASHEETはお客様のビジネスに役立ちますか? [ DONATE ] |
Alldatasheetは | 広告 | お問い合わせ | プライバシーポリシー | リンク交換 | メーカーリスト All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |