Moteur de recherche de fiches techniques de composants électroniques |
|
TL431LI Fiches technique(PDF) 12 Page - Texas Instruments |
|
|
TL431LI Fiches technique(HTML) 12 Page - Texas Instruments |
12 / 32 page 12 TL431LI TL432LI SLVSDQ6 – JULY 2018 www.ti.com Product Folder Links: TL431LI TL432LI Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated 9.3 Feature Description TL43xLI consists of an internal reference and amplifier that outputs a sink current based on the difference between the reference pin and the virtual internal pin. The sink current is produced by the internal Darlington pair, shown in the above schematic (Figure 19). A Darlington pair is used in order for this device to be able to sink a maximum current of 15 mA. When operated with enough voltage headroom ( ≥ 2.495 V) and cathode current (IKA), TL43xLI forces the reference pin to 2.495 V. However, the reference pin can not be left floating, as it needs IREF ≥ 0.8 µA (please see Specifications). This is because the reference pin is driven into an npn, which needs base current in order operate properly. When feedback is applied from the Cathode and Reference pins, TL43xLI behaves as a Zener diode, regulating to a constant voltage dependent on current being supplied into the cathode. This is due to the internal amplifier and reference entering the proper operating regions. The same amount of current needed in the above feedback situation must be applied to this device in open loop, servo or error amplifying implementations in order for it to be in the proper linear region giving TL43xLI enough gain. Unlike many linear regulators, TL43xLI is internally compensated to be stable without an output capacitor between the cathode and anode. However, if it is desired to use an output capacitor Figure 19 can be used as a guide to assist in choosing the correct capacitor to maintain stability. 9.4 Device Functional Modes 9.4.1 Open Loop (Comparator) When the cathode/output voltage or current of TL43xLI is not being fed back to the reference/input pin in any form, this device is operating in open loop. With proper cathode current (Ika) applied to this device, TL43xLI will have the characteristics shown in Figure 18. With such high gain in this configuration, TL43xLI is typically used as a comparator. With the reference integrated makes TL43xLI the preferred choice when users are trying to monitor a certain level of a single signal. SLVA987 more details on open loop comparator applications on the TL431LI. 9.4.2 Closed Loop When the cathode/output voltage or current of TL43xLI is being fed back to the reference/input pin in any form, this device is operating in closed loop. The majority of applications involving TL43xLI use it in this manner to regulate a fixed voltage or current. The feedback enables this device to behave as an error amplifier, computing a portion of the output voltage and adjusting it to maintain the desired regulation. This is done by relating the output voltage back to the reference pin in a manner to make it equal to the internal reference voltage, which can be accomplished through resistive or direct feedback. |
Numéro de pièce similaire - TL431LI |
|
Description similaire - TL431LI |
|
|
Lien URL |
Politique de confidentialité |
ALLDATASHEET.FR |
ALLDATASHEET vous a-t-il été utile ? [ DONATE ] |
À propos de Alldatasheet | Publicité | Contactez-nous | Politique de confidentialité | Echange de liens | Fabricants 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 |