Moteur de recherche de fiches techniques de composants électroniques |
|
TDA5144 Fiches technique(PDF) 10 Page - NXP Semiconductors |
|
TDA5144 Fiches technique(HTML) 10 Page - NXP Semiconductors |
10 / 20 page June 1994 10 Philips Semiconductors Product specification Brushless DC motor drive circuit TDA5144 Introduction (see Fig.8) Full-wave driving of a three phase motor requires three push-pull output stages. In each of the six possible states two outputs are active, one sourcing (H) and one sinking (L). The third output presents a high impedance (Z) to the motor, which enables measurement of the motor back-EMF in the corresponding motor coil by the EMF comparator at each output. The commutation logic is responsible for control of the output transistors and selection of the correct EMF comparator. In Table 1 the sequence of the six possible states of the outputs has been depicted. Table 1 Output states. Note 1. H = HIGH state; L = LOW state; Z = high-impedance OFF-state. The zero-crossing in the motor EMF (detected by the comparator selected by the commutation logic) is used to calculate the correct moment for the next commutation, that is, the change to the next output state. The delay is calculated (depending on the motor loading) by the adaptive commutation delay block. Because of high inductive loading the output stages contain flyback diodes. The output stages are also protected by a current limiting circuit and by thermal protection of the six output transistors. The detected zero-crossings are used to provide speed information. The information has been made available on the FG output pin. This is an open collector output and provides an output signal with a frequency that is half the commutation frequency. The system will only function when the EMF voltage from the motor is present. Therefore, a start oscillator is provided that will generate commutation pulses when no zero-crossings in the motor voltage are available. STATE MOT1(1) MOT2(1) MOT3(1) 1Z L H 2H L Z 3H Z L 4Z H L 5L H Z 6L Z H A timing function is incorporated into the device for internal timing and for timing of the reverse rotation detection. The TDA5144 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 TDA5144 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 TDA5144 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. |
Numéro de pièce similaire - TDA5144 |
|
Description similaire - TDA5144 |
|
|
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 |