Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
TDA4858 Datasheet(PDF) 11 Page - NXP Semiconductors |
|
TDA4858 Datasheet(HTML) 11 Page - NXP Semiconductors |
11 / 44 page 1997 Oct 27 11 Philips Semiconductors Product specification Economy Autosync Deflection Controller (EASDC) TDA4858 Supply voltage stabilizer, references and protection The EASDC provides an internal supply voltage stabilizer for excellent stabilization of all internal references. An internal gap reference especially designed for low-noise is the reference for the internal horizontal and vertical supply voltages. All internal reference currents and drive current for the vertical output stage are derived from this voltage via external resistors. A special protection mode has been implemented in order to protect the deflection stages and the picture tube during start-up, shut-down and fault conditions. This protection mode can be activated as shown in Table 3. Table 3 Activation of protection mode When protection mode is active, several pins of the ASDC are forced into a defined state: HDRV (horizontal driver output) is floating BDRV (B+ control driver output) is floating VOUT1 and VOUT2 (vertical outputs) are floating CLBL provides a continuous blanking signal The capacitor at HPLL2 is discharged. ACTIVATION RESET Low supply voltage at pin 9 increase supply voltage X-ray protection XRAY (pin 2) triggered remove supply voltage HPLL2 (pin 31) pulled to ground release pin 31 If the protection mode is activated via the supply voltage at pin 9, all these actions will be performed in a well defined sequence (see Fig.14). For activation via X-ray protection or HPLL2 all actions will occur simultaneously. The return to normal operation is performed in accordance with the start-up sequence in Fig.14a, if the reset was caused by the supply voltage at pin 9. The first action with increasing supply voltage is the activation of continuous blanking at CLBL. When the threshold for activation of HDRV is passed, an internal current begins to charge the external capacitor at HPLL2 and a PLL2 soft start sequence is performed (see Fig.15). In the beginning of this phase the horizontal driver stage generates very small output pulses. The width of these pulses increases with the voltage at HPLL2 until the final duty cycle is reached. Then the PLL2 voltage passes the threshold for activation of BDRV, VOUT1 and VOUT2. For activation of these pins not only the PLL2 voltage, but also the supply voltage must have passed the appropriate threshold. A last pair of thresholds has to be passed by PLL2 voltage and supply voltage before the continuous blanking is finally removed, and the operation of PLL2 and frequency-locked loop is enabled. A return to the normal operation by releasing the voltage at HPLL2 will lead to a slightly different sequence. Here the activation of all functions is influenced only by the voltage at HPLL2 (see Fig.15). Application hint: Internal discharge of the capacitor at HPLL2 will only be performed, if the protection mode was activated via the supply voltage or X-ray protection. |
Número de pieza similar - TDA4858 |
|
Descripción similar - TDA4858 |
|
|
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 |