LM621 National Semiconductor, LM621 Datasheet
LM621
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LM621 Summary of contents
Page 1
... DC motors The part is compatible with both three- and four-phase motors It can directly drive the power switching devices used to drive the motor The LM621 pro- vides an adjustable dead-time circuit to eliminate ‘‘shoot- through’’ current spiking in the power switching circuitry ...
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... CC2 OUT Output Rise Time (sourcing) C Output Fall Time (sinking) C Propagation Delay Dead-Time Off (Hall Input to Output) (See Notes) Operating Ambient Temperature Range LM621 Storage Temperature Range 7V a Junction Temperature 45V a ESD Susceptibility (Note 10 Lead Temperature N pkg 20 mA ...
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Electrical Characteristics (See Notes) (Continued) Parameter Conditions DEAD-TIME SECTION High Level Input Voltage DIRECTION Pin 3 e OUTPUT INHIBIT DEAD-TIME ENABLE Pin 17 High Level Input Current DIRECTION Pin 3 e OUTPUT INHIBIT DEAD-TIME ENABLE Low ...
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... Pins 14 thru 16 SINK OUTPUTS The three current-sinking outputs which drive the external power devices that drive the motor Pin 17 OUTPUT INHIBIT This input disables the LM621 outputs It is typically driven by the magnitude signal from an external sign magnitude PWM generator Pin 17 outputs off ...
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... Three outputs source current the remaining three sink current The output transistors provide outputs for driving devices 40V output swings for driving MOSFETs The LM621 logic is powered from 5V The undervoltage lockout section monitors the V ...
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... HS1 and HS2 When using the LM621 to run a four-phase motor the HS2 signal is connect both the HS2 and HS3 chip inputs 6 Source Outputs off off ON ...
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Dead-Time Feature The DEAD-TIME ENABLE input is used to enable this fea- ture (by connecting 5V to pin 3) The reason for providing a this feature is that the external power switches are usually totem-pole structures Since these structures switch ...
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... Typical Applications THREE-PHASE EXAMPLES Figure typical LM621 application This circuitry is for use with a three-phase motor having 30-degree sensor phasing as indicated by connection of the 30 60 SELECT input pin logic ‘‘1’’ ( ...
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Typical Applications (Continued) FIGURE 5 Commutation of Three-Phase Motor (MOSFET Switches 8679 – 10 ...
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... With the LM621 outputs connected as shown this approach pro- vides the needed power-switch drive signals for a four- phase motor Note that only four of the six LM621 outputs FIGURE 6 Commutation of Four-Phase Motor (SINK 1 and ...
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Typical Applications (Continued) FIGURE 7 Half-Wave Drive of Y-Configured Motor 8679 – 12 ...
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... National does not assume any responsibility for use of any circuitry described no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications Molded Dual-in-Line Package (N) Order Number LM621N NS Package Number N18A 2 A critical component is any component of a life ...