AN1625 STMicroelectronics, AN1625 Datasheet - Page 36

• Manufacturer Part Number: AN1625
• Description: L6235 THREE PHASE BRUSHLESS DC MOTOR DRIVER
• Manufacturer: STMicroelectronics

AN1625 APPLICATION NOTE
the reference voltage provided to the Vref pin of the L6235 (in torque mode) or to the error amplifier, U2 (in
speed mode); R20, C11 make up a low-pass filters to provide an external reference voltage by a PWM output
of a C (see also the Reference Voltage section). R10, C8 are used to set the off-time and R11, C9 set the
duration of the TACHO output pulses.
The 5V voltage for logic inputs and for the reference voltage is obtained from R1, D3. For supply voltages great-
er than 20V, R1 must be replaced with a higher value resistor. The jumper JP1 and JP2 allow disconnecting the
internal zener diode network, in case the 5V voltage is provided through pin 11 of CN5 (for example an external
µC board can provide 5 V to the evaluation board). Also CN2 connector can be used to provide an external 5 V
voltage to the board. CN2, or pin 1 of CN5, can also be used to provide a 5 V voltage to external circuits. In this
case only a small current can be drawn form the board, depending on the supply voltage and R1 value. Figure
41, Figure 42, Figure 43 show the component placement and the two layers layout of the L6235N Evaluation
Board.
A large GND area has been used, to guarantee minimal noise and good power dissipation for the device.
Figure 39. EVAL6235N.
4.2.1 Important Notes
JP1 : close for use with PractiSPIN ST7 board
JP2 : close for use with PractiSPIN ST7 board
C6 : recommended change to 5.6 nF for safe Overcurrent protection
R2 : recommended change to 100 k for safe Overcurrent protection
R6 : recommended change to 100 k (and remove R2) if EN pin is driven from the CN4 connector (for example
R22 : set the maximum current obtainable through PractiSPIN (see PractiSPIN documentation)
R1 : recommended change to adequate value (depending on supply voltage) to obtain 5V across D3
S1 : move first switch in TRQ position for use with PractiSPIN ST7 board
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with PractiSPIN ST7 board) for safe Overcurrent protection
1
of S1
st
switch
R2
R6
R22
C6
JP2
JP1
R1