SH7137_09 Datasheet, PDF (10/24 Pages) Renesas Technology Corp – Output of Complementary Pairs of PWM Signals in Three Phases

SH7280 Group
MTU2: Output of Complementary Pairs of PWM Signals in Three Phases
(Complementary PWM Mode)
2.2.3 Examples of Output with Desired PWM Duty Cycles
Table 4 gives relations between register settings for PWM duty cycle and the behavior of the positive and inverse
waveforms in one phase. In complementary PWM mode, when the value in a comparison register (TGRB_3, in this
sample program) is H'0000, the positive output remains ON while the inverse output remains OFF; i.e. the output levels
are fixed. Furthermore, when the value in the comparison register is greater than or equal to the value in the TGRA_3
register, the level of the positive signal is fixed to the OFF state while the level of the inverse signal is fixed to the ON
state.
Figures 9 and 10 shows examples of output waveforms of the positive and inverse signals. When changing the PWM
duty cycle, make sure that the values are set in the corresponding buffer registers rather than directly in the comparison
registers and that changing comparison registers should be made via the buffer registers.
Table 4 Examples of Setting that Control the PWM Duty Cycle and Output Waveforms
Output Waveforms*¹
Value in TGRB_3
Positive output
(TIOC3B pin)
Inverse output
(TIOC3D pin)
Waveform
Chart
TGRB_3 ≥TGRA_3
Fixed to the OFF state
(high)
Fixed to the ON state
(low)
Figure 9 (a)
Between TGRA_3 and
TCDR
Fixed to the OFF state
(high)
Output of the OFF waveform —
(pulse)
TGRB_3 = TCDR
Fixed to the OFF state
(high)
Output of the OFF waveform
(to be a pulse twice the
width of the short-circuit
prevention interval)
Figure 9 (b)
Between (TCDR – Td) and
TCDR
Output of the ON waveform Output of the OFF waveform —
(pulse)
TGRB_3 = (TCDR – Td)
Between (TDDR × 2) and
(TCDR – Td)
TGRB_3 = (TDDR × 2)
Output of the ON waveform Output of the OFF waveform
(to be a pulse twice the
(to be a pulse four times the
width of the short-circuit
width of the short-circuit
prevention interval)
prevention interval)
Output of complementary PWM waveforms
Figure 9 (c)
—
Output of the OFF waveform
(to be a pulse four times the
width of the short-circuit
prevention interval)
Output of the ON waveform
(to be a pulse twice the
width of the short-circuit
prevention interval)
Figure 10 (a)
Between TDDR and (TDDR Output of the OFF waveform Output of the ON waveform —
× 2)
(pulse)
TGRB_3 = TDDR
Output of the OFF waveform
(to be a pulse twice the
width of the short-circuit
prevention interval)
Fixed to the OFF state
(high)
Figure 10 (b)
Between H'0000 and TDDR Output of the OFF waveform Fixed to the OFF state
—
(pulse)
(high)
TGRB_3 = H'0000
Fixed to the ON state (low) Fixed to the OFF state
(high)
Figure 10 (c)
Note: 1. The active level of the PWM output is set to low. The descriptions of the output waveforms refer to
the positive and inverse signals for a single complementary pair.
REJ06B0887-0100/Rev.1.00
June 2009
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