WAVEFORMS OF 1-BIT CIRCUIT
2.00V/div AD IC Output 2.00V/div + Side
2.00 V/div 2.00 V/div LEVEL SHIFT OUT
T
1 2
5V
T
2
5 6
DEAD TIME
1
- Side 500 ns/div Amplitude from 0 to 5 V 194.545465 µs 520 mV
50.0 ns/div 0.0 s -12.30 V Dead time is generated by level shift input. Leading edge is delayed at CR, passing R at DI. Set value: 20 - 25 nsec.
ZOOM UP
2.00 V/div
2.00 V/div
10.0 V/div
10.0 V/div
3
2
+ FETOUT + SIDE
2
11
AD IC NF IN
T
12
1
- SIDE
1
4
500 ns/div 194.545465 µs -12.30 V
500 ns/div Waveforms before low-pass filters at both ends of the speaker. H-bridge may be considered as BTL. However, here and at the gate drive, dead time is not observed; since bootstrap operates based on output, DEAD TIME part is in floating condition. The waveform on the HIGH side shows that only the booted voltage lowers. 194.545465 µs -12.3 V
In partial pressure OUT, 4 to 7 V amplitude of GND reference is observed. In IC of 75 kohms, the reference is 2.5 V because of VREF. Due to imaginary GND of operational amplifier inside IC, the waveform cannot be monitored. This waveform is partial pressure OUT.
