 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
TDA5145T Datasheet(PDF) 11 Page - NXP Semiconductors |
|
||||||||||||||||||||||||||||||
TDA5145T Datasheet(HTML) 11 Page - NXP Semiconductors |
|
|
11 / 24 page  June 1994 11 Philips Semiconductors Product specification Brushless DC motor drive circuit TDA5145 provided that will generate commutation pulses when no zero-crossings in the motor voltage are available. A timing function is incorporated into the device for internal timing and for timing of the reverse rotation detection. The TDA5145 also contains an uncommitted transconductance amplifier (OTA) that can be used as a control amplifier. The output is capable of directly driving an external power transistor. The TDA5145 is designed for systems with low current consumption: use of I2L logic, adaptive base drive for the output transistors (patented). Adjustments The system has been designed in such a way that the tolerances of the application components are not critical. However, the approximate values of the following components must still be determined: • The start capacitor; this determines the frequency of the start oscillator. • The two capacitors in the adaptive commutation delay circuit; these are important in determining the optimum moment for commutation, depending on the type and loading of the motor. • The timing capacitor; this provides the system with its timing signals. THE START CAPACITOR (CAP-ST) This capacitor determines the frequency of the start oscillator. It is charged and discharged, with a current of 2 µA, from 0.05 to 2.2 V and back to 0.05 V. The time taken to complete one cycle is given by: tstart = (2.15 × C) s (with C in µF) The start oscillator is reset by a commutation pulse and so is only active when the system is in the start-up mode. A pulse from the start oscillator will cause the outputs to change to the next state (torque in the motor). If the movement of the motor generates enough EMF the TDA5145 will run the motor. If the amount of EMF generated is insufficient, then the motor will move one step only and will oscillate in its new position. The amplitude of the oscillation must decrease sufficiently before the arrival of the next start pulse, to prevent the pulse arriving during the wrong phase of the oscillation. The oscillation of the motor is given by: where: Kt = torque constant (N.m/A) I = current (A) p = number of magnetic pole-pairs J = inertia J (kg.m2) Example: J = 72 × 10−6 kg.m2, K = 25 × 10−3 N.m/A,p=6 and I = 0.5 A; this gives fosc = 5 Hz. If the damping is high then a start frequency of 2 Hz can be chosen or t = 500 ms, thus C = 0.5/2 = 0.25 µF (choose 220 nF). THE ADAPTIVE COMMUTATION DELAY (CAP-CD AND CAP-DC) In this circuit capacitor CAP-CD is charged during one commutation period, with an interruption of the charging current during the diode pulse. During the next commutation period this capacitor (CAP-CD) is discharged at twice the charging current. The charging current is 8.1 µA and the discharging current 16.2 µA; the voltage range is from 0.9 to 2.2 V. The voltage must stay within this range at the lowest commutation frequency of interest, fC1: (C in nF) If the frequency is lower, then a constant commutation delay after the zero-crossing is generated by the discharge from 2.2 to 0.9 V at 16.2 µA; maximum delay = (0.076 × C) ms (with C in nF) Example: nominal commutation frequency = 900 Hz and the lowest usable frequency = 400 Hz; so: (choose 18 nF) The other capacitor, CAP-DC, is used to repeat the same delay by charging and discharging with 15.5 µA. The same value can be chosen as for CAP-CD. Figure 9 illustrates typical voltage waveforms. f osc 1 2 π K t I × p × J ----------------------- ----------------------------------- = C 8.1 10 6 – × f 1.3 × -------------------------- 6231 f C1 ------------- == CAP-CD 6231 400 ------------- 15.6 == |
Similar Part No. - TDA5145T |
|
Similar Description - TDA5145T |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.NET |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List 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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
