データシートサーチシステム |
|
LM25088 データシート(PDF) 10 Page - Texas Instruments |
|
LM25088 データシート(HTML) 10 Page - Texas Instruments |
10 / 33 page TON Sample and Hold DC Level V/A 10 x RS RAMP TON (5 PA/V x (VIN ± VOUT) + 25 PA) x CRAMP LM25088 SNVS609G – DECEMBER 2008 – REVISED MARCH 2011 www.ti.com Error Amplifier and PWM Comparator The internal high gain error amplifier generates an error signal proportional to the difference between the regulated output voltage and an internal precision voltage reference (1.205V). The output of the error amplifier is connected to the COMP pin allowing the user to connect loop compensation components. Generally a type II network, as illustrated in Figure 15, is sufficient. This network creates a pole at DC, a mid-band zero for phase boost and a high frequency pole for noise reduction. The PWM comparator compares the emulated current signal from the RAMP generator to the error amplifier output voltage at the COMP pin. A typical control loop gain/phase plot is shown in Typical Performance Characteristics section of this document. Ramp Generator The ramp signal used for the pulse width modulator in current mode control is typically derived directly from the buck switch current. This signal corresponds to the positive slope portion of the buck inductor current. Using this signal for the PWM ramp simplifies the control loop transfer function to a single pole response and provides inherent input voltage feed-forward compensation. The disadvantage of using the buck switch current signal for PWM control is the large leading edge spike due to circuit parasitics which must be filtered or blanked. Also, the current measurement may introduce significant propagation delays. The filtering time, blanking time and propagation delay limit the minimum achievable pulse width. In applications where the input voltage may be relatively large in comparison to the output voltage, controlling small pulse widths and duty cycles is necessary for regulation. The LM25088 utilizes a unique ramp generator which does not actually measure the buck switch current but rather reconstructs or emulates the signal. Emulating the inductor current provides a ramp signal that is free of leading edge spikes and measurement or filtering delays. The current reconstruction is comprised of two elements; a sample & hold DC level and an emulated current ramp. Figure 17. Composition of Current Sense Signal 10 Submit Documentation Feedback Copyright © 2008–2011, Texas Instruments Incorporated Product Folder Links: LM25088 |
同様の部品番号 - LM25088_14 |
|
同様の説明 - LM25088_14 |
|
|
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 |