 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
A3941KLP-T Datasheet(PDF) 7 Page - Allegro MicroSystems |
|
||||||||||||||||||||||||||||||
A3941KLP-T Datasheet(HTML) 7 Page - Allegro MicroSystems |
|
|
7 / 20 page  Automotive Full Bridge MOSFET Driver A3941 7 Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com The A3941 is a full-bridge MOSFET driver (pre-driver) requiring a single unregulated supply of 7 to 50 V. It includes an integrated 5 V logic supply regulator. The four high current gate drives are capable of driving a wide range of N-channel power MOSFETs, and are configured as two high-side drives and two low-side drives. The A3941 provides all the necessary circuits to ensure that the gate-source voltage of both high-side and low-side external FETs are above 10 V, at supply voltages down to 7 V. For extreme battery voltage drop conditions, correct functional operation is guaranteed at supply voltages down to 5.5 V, but with a reduced gate drive voltage. The A3941 can be driven with a single PWM input from a microcontroller and can be configured for fast or slow decay. Fast decay can provide four-quadrant motor control, while slow decay is suitable for two-quadrant motor control or simple induc- tive loads. In slow decay, current recirculation can be through the high-side or the low-side MOSFETs. In either case, bridge efficiency can be enhanced by synchronous rectification. Cross- conduction (shoot through) in the external bridge is avoided by an adjustable dead time. A low power sleep mode allows the A3941, the power bridge, and the load to remain connected to a vehicle battery supply without the need for an additional supply switch. The A3941 includes a number of protection features against undervoltage, overtemperature, and power bridge faults. Fault states enable responses by the device or by the external control- ler, depending on the fault condition and logic settings. Two fault flag outputs, FF1 and FF2, are provided to signal detected faults to an external controller. Power Supplies A single power supply connection is required to the VBB pin through a reverse voltage protection circuit. The supply should be decoupled with a ceramic capacitor connected close to the VBB and ground pins. The A3941 operates within specified parameters with a VBB supply from 7 to 50 V and functions correctly with a supply down to 5.5 V. This provides a very rugged solution for use in the harsh automotive environment. V5 Pin A 5 V low current supply for external pullup resistors is provided by an integrated 5 V regulator. This regulator is also used by the internal logic circuits and must always be decoupled by at least a 100 nF capacitor between the V5 pin and GND. The 5 V regulator is disabled when RESET is held low. Gate Drives The A3941 is designed to drive external, low on-resistance, power N-channel MOSFETs. It supplies the large transient cur- rents necessary to quickly charge and discharge the external FET gate capacitance in order to reduce dissipation in the external FET during switching. The charge and discharge rate can be controlled using an external resistor in series with the connection to the gate of the FET. Gate Drive Voltage Regulation The gate drives are powered by an internal regulator which limits the supply to the drives and therefore the maximum gate voltage. When the VBB supply is greater than about 16 V, the regulator is a simple linear regulator. Below 16 V, the regulated supply is maintained by a charge pump boost converter, which requires a pump capacitor connected between the CP1 and CP2 pins. This capacitor must have a mini- mum value of 220 nF, and is typically 470 nF. The regulated voltage, nominally 13 V, is available on the VREG pin. A sufficiently large storage capacitor must be connected to this pin to provide the transient charging current to the low-side drives and the bootstrap capacitors. Top-off Charge Pump An additional top-off charge pump is provided for each phase. The charge pumps allow the high-side drives to maintain the gate voltage on the external FETs indefi- nitely, ensuring so-called 100% PWM if required. This is a low current trickle charge pump, and is operated only after a high-side FET has been signaled to turn on. The floating high-side gate drive requires a small bias current (<20 μA) to maintain the high- level output. Without the top-off charge pump, this bias current would be drawn from the bootstrap capacitor through the Cx pin. The charge pump provides sufficient current to ensure that the bootstrap voltage and thereby the gate-source voltage is main- tained at the necessary level. Note that the charge required for initial turn-on of the high-side gate is always supplied by the bootstrap capacitor. If the bootstrap capacitor becomes discharged, the top-off charge pump will not provide sufficient current to allow the FET to turn on. Functional Description |
Similar Part No. - A3941KLP-T |
|
Similar Description - A3941KLP-T |
|
|
|
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
