Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
TEA2261 Datasheet(PDF) 7 Page - STMicroelectronics |
|
TEA2261 Datasheet(HTML) 7 Page - STMicroelectronics |
7 / 11 page TEA2261/0 7/11 The magnetization state of the transformer is checked by sensing the voltage across a winding of the transformer (generally the same which sup- plies the TEA2261). This is made by connecting a resistor between this winding and the demagneti- zation sensing input of the circuit (Pin 1). SECURITY FUNCTIONS OF THE TEA2260 (see flowchart below) Undervoltage Detection. This protection works in association with the starting device “VCC switch” (see paragraph Starting-mode - stand-by mode). If VCC is lower than VCCstop (typically 7.4V) output pulses are inhibited, in order to avoid wrong oper- ation of the power supply or bad power transistor drive. Overvoltage Detection. If VCC exceeds VCCmax (typically 15.7V) output pulses are inhibited. Re- starting of the power supply is obtained by reduc- ing VCC below VCCstop. Current Limitation of the Power Transistor. The current is measured by a shunt resistor. A double threshold system is used: – When the first threshold (VIM1) is reached, the conduction of the power transistor is stopped un- til the end of the period: a new conduction signal is needed to obtain conduction again. – Furthermore as long as the first threshold is reached (it means during several periods), an ex- ternal capacitor C2 is charged. When the voltage across the capacitor reaches VC2 (typically 2.55V) the output is inhibited. This is called the “repetitive overload protection”. If the overload disappears before VC2 is reached, C2 is dis- charged, so transient overloads are tolerated. – Second current limitation threshold (VIM2). When this threshold is reached the output of the circuit is immediately inhibited. This protection is helpful in case of hard overload for example to avoid the magnetization of the transformer. Restart of the Power Supply. After stopping due to VC2, VIM2, VCCMax or VCCstop triggering, re- start of the power supply can be obtained by the normal operating of the “VCC switch” but thanks to an integrated counter, if normal restart cannot be obtained after three trials, the circuit is definitively stopped. In this case it is necessary to reduce VCC below approximately 5V to reset the circuit. From a practical point of view, it means that the power supply has to be temporarily disconnected from any power source to get the restart. |
Número de pieza similar - TEA2261 |
|
Descripción similar - TEA2261 |
|
|
Enlace URL |
Política de Privacidad |
ALLDATASHEET.ES |
¿ALLDATASHEET es útil para Ud.? [ DONATE ] |
Todo acerca de Alldatasheet | Publicidad | Contáctenos | Política de Privacidad | Intercambio de Enlaces | Lista de Fabricantes 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 |