データシートサーチシステム |
|
LM2743 データシート(PDF) 11 Page - Texas Instruments |
|
LM2743 データシート(HTML) 11 Page - Texas Instruments |
11 / 37 page VOUT2 = VOUT1 RT1 RT1 + RT2 5V 1.8V VOUT1 VOUT2 0.65 = VOUT1 RT1 RT1 + RT2 Master Power Supply VOUT1 = 5V SS/TRACK LM2743 RT2 1 k: RT1 150: RFB2 10 k: RFB1 5 k: FB VOUT2 = 1.8V VSS = 0.65V VFB LM2743 www.ti.com SNVS276F – MAY 2004 – REVISED JANUARY 2012 Figure 3. Tracking Circuit One way to use the tracking feature is to design the tracking resistor divider so that the master supply’s output voltage (VOUT1) and the LM2743’s output voltage (represented symbolically in Figure 3 as VOUT2, i.e. without explicitly showing the power components) both rise together and reach their target values at the same time. For this case, the equation governing the values of the tracking divider resistors RT1 and RT2 is: (4) The current through RT1 should be about 3 mA to 4 mA for precise tracking. The final voltage of the SS/TRACK pin should be set higher than the feedback voltage of 0.6V (say about 0.65V as in the above equation). If the master supply voltage was 5V and the LM2743 output voltage was 1.8V, for example, then the value of RT1 needed to give the two supplies identical soft-start times would be 150 Ω. A timing diagram for the equal soft-start time case is shown in Figure 4. Figure 4. Tracking with Equal Soft-Start Time TRACKING A VOLTAGE SLEW RATE The tracking feature can alternatively be used not to make both rails reach regulation at the same time but rather to have similar rise rates (in terms of output dV/dt). This method ensures that the output voltage of the LM2743 always reaches regulation before the output voltage of the master supply. Because the output of the master supply is divided down, in order to track properly the output voltage of the LM2743 must be lower than the voltage of the master supply. In this case, the tracking resistors can be determined based on the following equation: (5) Copyright © 2004–2012, Texas Instruments Incorporated Submit Documentation Feedback 11 Product Folder Links: LM2743 |
同様の部品番号 - LM2743_14 |
|
同様の説明 - LM2743_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 |