Moteur de recherche de fiches techniques de composants électroniques |
|
TEA1208T Fiches technique(PDF) 6 Page - NXP Semiconductors |
|
TEA1208T Fiches technique(HTML) 6 Page - NXP Semiconductors |
6 / 20 page 2002 Nov 15 6 Philips Semiconductors Product specification High efficiency DC/DC converter TEA1208T Start-up Start-up from low input voltage in up conversion is realized by an independent start-up oscillator, which starts switching the N-type power MOSFET as soon as the voltage at pin UPOUT/DNIN is measured to be sufficiently high. The switch actions of the start-up oscillator will increase the output voltage. As soon as the output voltage is high enough for normal regulation, the digital control system takes over the control of the power MOSFETs. Undervoltage lockout As a result of too high a load or disconnection of the input power source, the output voltage can drop so low that normal regulation cannot be guaranteed. In this case, the device switches back to start-up mode. If the output voltage drops even further, switching stops completely. Shut-down When the shut-down input is made HIGH, the converter disables both power switches reducing the power consumption to a few microamperes. Power switches The device has two power switches - one N-type and one P-type power MOSFET, having a typical drain-to-source resistance of 0.20 Ω and 0.22 Ω respectively. The maximum average current in the power switches is 0.30 A at Tamb =80 °C. Temperature protection In PWM mode, the device will stop operating if the die temperature is too high (typically 175 °C). Operation resumes when the die temperature falls below 175 °C. As a result, low-frequency cycling between the on and off state will occur. Note that if the temperature of the device approaches Tmax, the actual maximum parameter limits may be very different from those specified. Current limiters If the current in one of the power switches exceeds its limit in the PWM mode, the current ramp is stopped immediately, and the next switching phase is entered. Current limiting is required to enable optimal use of energy in Li-ion batteries, and to keep power conversion efficient during temporary high loads. Furthermore, current limiting protects the IC against overload conditions, inductor saturation, etc. The current limiting level is set by an external resistor. External synchronization If an external high-frequency clock is applied to the synchronization clock input, the switching frequency in PWM mode will be exactly that frequency divided by 22. In the PFM mode, the switching frequency is always lower. The quiescent current of the device increases when external clock pulses are applied. When no external synchronization is necessary, the synchronization clock input must be connected to ground level. Behaviour at input voltage exceeding the specified range In general, an input voltage exceeding the specified range is not recommended since instability may occur. There are two exceptions: • Up conversion: at an input voltage higher than the target output voltage, but up to 6 V, the converter will stop switching and the internal P-type power MOSFET will be conducting. The output voltage will equal the input voltage minus some resistive voltage drop. The current limiting function is not active. • Down conversion: when the input voltage is lower than the target output voltage, but higher than 2.8 V, the P-type power MOSFET will stay conducting resulting in an output voltage being equal to the input voltage minus some resistive voltage drop. The current limiting function remains active. |
Numéro de pièce similaire - TEA1208T |
|
Description similaire - TEA1208T |
|
|
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 |