Microchip Technology DM164130-10 User Manual
Main PSMC Configuration GUI
2012-2013 Microchip Technology Inc.
DS40001671B-page 23
2.19.1
Dead-Band Control
Each of the six complementary modes contains two dead-band control blocks. One
control delays the turn-on of the normal PWM output(s) and the other control delays the
turn-on of the complementary PWM output(s). Dead-band control does not delay the
turn-off of either normal or complementary outputs.
control delays the turn-on of the normal PWM output(s) and the other control delays the
turn-on of the complementary PWM output(s). Dead-band control does not delay the
turn-off of either normal or complementary outputs.
2.19.1.1 WHAT IS DEAD BAND?
Complementary outputs are generally used to drive power devices connected in series
between the power rails. The complementary outputs drive the two power devices such
that only one is on at a time, connecting one of the power rails to the load. When the
PWM output is active, then one rail is connected to the output. When the complement
is active, then the other rail is connected to the output. The turn-on time of a power
device is generally faster than the turn-off time. It is necessary therefore, to disable the
drives to both power devices for at least the activation difference to prevent both
devices from conducting at the same time. This is accomplished with the dead-band
time.
Click on either dead-band block to open the rising or falling dead-band control GUI
shown in
between the power rails. The complementary outputs drive the two power devices such
that only one is on at a time, connecting one of the power rails to the load. When the
PWM output is active, then one rail is connected to the output. When the complement
is active, then the other rail is connected to the output. The turn-on time of a power
device is generally faster than the turn-off time. It is necessary therefore, to disable the
drives to both power devices for at least the activation difference to prevent both
devices from conducting at the same time. This is accomplished with the dead-band
time.
Click on either dead-band block to open the rising or falling dead-band control GUI
shown in
. To enable dead band, click the switch to connect the AND gate
output to the dead-band output. Enter the desired dead-band time in the text box.
Dead band operates as follows: When the input transitions from high-to-low the output
goes low immediately. When the input transitions from low-to-high then the output
transition is delayed by the dead-band time.
Note that the dead-band controls are identical for all modes. In other words, changes
made to the rising dead-band control in one mode will appear in the rising dead-band
control of all other modes. The same is true for the falling dead-band control.
Dead band operates as follows: When the input transitions from high-to-low the output
goes low immediately. When the input transitions from low-to-high then the output
transition is delayed by the dead-band time.
Note that the dead-band controls are identical for all modes. In other words, changes
made to the rising dead-band control in one mode will appear in the rising dead-band
control of all other modes. The same is true for the falling dead-band control.
FIGURE 2-9:
DEAD-BAND CONTROL
2.19.2
SPWM: Single PWM Mode
Single PWM mode is selected by clicking on the SPWM tab, as shown in
This mode directs the single PWM signal to the six output channels. This mode enables
output steering which is a means of enabling or disabling any combination of the six
channels. Output steering selection is discussed in the output control section. Output
steering can be used to switch the output from one pin to another pin or to enable
several outputs simultaneously, so they can be connected in parallel to boost the output
current drive.
output steering which is a means of enabling or disabling any combination of the six
channels. Output steering selection is discussed in the output control section. Output
steering can be used to switch the output from one pin to another pin or to enable
several outputs simultaneously, so they can be connected in parallel to boost the output
current drive.