Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
DRV401 Datasheet(PDF) 16 Page - Texas Instruments |
|
DRV401 Datasheet(HTML) 16 Page - Texas Instruments |
16 / 36 page DRV401 SBVS070B − JUNE 2006 − REVISED MAY 2009 www.ti.com 16 COMPENSATION DRIVER The compensation coil driver provides the driving current for the compensation coil. A fully differential driver stage offers high signal voltages to overcome the wire resistance of the coil with only +5V supply. The compensation coil is connected between ICOMP1 and ICOMP2, both generating an analog voltage across the coil (see Figure 3) that turns into current from the wire resistance (and eventually from the inductance). The compensation current represents the primary current transformed by the turns ratio. A shunt resistor is connected in this loop and the high-precision difference amplifier translates the voltage from this shunt to an output voltage. Both compensation driver outputs provide low impedance over a wide frequency range to insure smooth transitions between the closed-loop compensation frequency range and the high-frequency range, where the primary winding directly couples the primary current into the compensation coil at a rate set by the winding ratio. The two compensation driver outputs are designed with protection circuitry to handle inductive energy. However, additional external protection diodes might be necessary for high current sensors. For reliable operation, a wire break in the compensation circuit can be detected. If the feedback loop is broken, the integrating filter drives the outputs ICOMP1 and ICOMP2 to the opposite rails. With one of these pins coming within 300mV to ground, a comparator tests for a minimum current flowing between ICOMP1 and ICOMP2. If this current stays below the threshold current level for at least 100 µs, the ERROR pin is asserted active (low). The threshold current level for this test is less than 57mA at 25 °C and 65mA at −40°C, if the ICOMP pins are fully railed (see the Typical Characteristics). For sensors with high winding resistance (compensation coil resistance + RSHUNT) or connected to an external compensation driver, this function should be disabled by pulling the CCdiag pin low. R MAX + V OUT 65mA Where: VOUT equals the peak voltage between ICOMP1 and ICOMP2 at a 65mA drive current. RMAX equals the sum of the coil and the shunt resistance. EXTERNAL COMPENSATION COIL DRIVER An external driver for the compensation coil can be connected to the ICOMP1 and ICOMP2 outputs. To prevent a wire break indication, CCdiag has to be asserted low. An external driver can provide both a higher drive voltage and more drive current. It also moves the power dissipation to the external transistors, thereby allowing a higher winding resistance in the compensation coil and more current. Figure 4 shows a block diagram of an external compensation coil driver. To drive the buffer, either one or both ICOMP outputs can be used. Note, however, that the additional voltage gain could cause instability of the loop. Therefore, the internal gain can be reduced by approximately 8dB by asserting the GAIN pin high. RSHUNT is connected to GND to allow for a single-ended external compensation driver. The differential amplifier can continue to sense the voltage, and used for the gain and over-range comparator or ERROR flag. DRV401 External Buffer V+ V − Compensation Coil R SHUNT I COMP1 I COMP2 Figure 4. DRV401 with External Compensation Coil Driver and RSHUNT Connected to GND (1) |
Número de pieza similar - DRV401_15 |
|
Descripción similar - DRV401_15 |
|
|
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 |