UPD16857 View Datasheet(PDF) - NEC => Renesas Technology
Part Name
Description
MFG CO.
UPD16857 Datasheet PDF : 16 Pages
| |||
ABOUT SWITCHING OPERATION
When output A is switched as shown in the figure on the right, a dead
time (time during which both Pch and Nch are off) elapses to prevent
through current. Therefore, the waveform of output A (rise time, fall time,
and delay time) changes depending on whether output B is fixed to the
high or low level.
The output voltage waveforms of A in response to an input waveform
where output B is fixed to the low level (1) or high level (2) are shown
below.
µPD16857
VM
Pch
A
Pch
B
Nch
Nch
(1) Output B: Fixed to low level
Output A: Switching operation (Operations of Pch switch and Nch switch are shown.)
Input waveform
Dead time
Pch : OFF → OFF → ON →
Nch : ON → OFF → OFF →
⋅ ⋅ ⋅ ⋅ ON ⋅ ⋅ ⋅ ⋅
⋅ ⋅ ⋅ ⋅ OFF ⋅ ⋅ ⋅ ⋅
OFF → OFF →
OFF → ON →
Voltage waveform at point A
Current OFF
Current ON
Output A goes into high-impedance state and is in an undefined status during the dead time period. But,
because output B is pulled down by the load, a low level is output to A.
(2) Output B: Fixed to high level
Output A: Switching operation (Operations of Pch switch and Nch switch are shown.)
Input waveform
Dead time
Pch : OFF → OFF → ON →
Nch : ON → OFF → OFF →
Voltage waveform at point A
Current OFF
⋅ ⋅ ⋅ ⋅ ON ⋅ ⋅ ⋅ ⋅
⋅ ⋅ ⋅ ⋅ OFF ⋅ ⋅ ⋅ ⋅
OFF → OFF →
OFF → ON →
Current ON
Output A goes into high-impedance state and is in an undefined status during the dead time period. But,
because output B is pulled up by the load, a high level is output to A.
10
Data Sheet S13908EJ1V0DS00
Share Link: 