DRV104_16 Datasheet, PDF (9/26 Pages) Texas Instruments – 1.2A PWM High-Side Driver for Solenoids, Coils, Valves, Heaters, and Lamps

R_FREQ
only
Time (10µs)
With
100pF in
Parallel
with R_FREQ
FIGURE 5. Output Waveform at High Load Current.
ADJUSTABLE DUTY CYCLE (PWM MODE)
The DRV104’s externally adjustable duty cycle provides an
accurate means of controlling power delivered to a load.
Duty cycle can be set over a range of 10% to 90% with an
external resistor, analog voltage, or the voltage output of a
D/A converter. A low duty cycle results in reduced power
dissipation in the load. This keeps the DRV104 and the load
cooler, resulting in increased reliability for both devices.
Resistor Controlled Duty Cycle
Duty cycle is easily programmed by connecting a resistor
(R_PWM) between Duty Cycle Adjust (pin 1) and ground. High
resistor values correspond to high duty cycles. At 100kHz,
the range of adjustable duty cycle is limited to 10% to 70%.
Table III provides resistor values for typical duty cycles.
Resistor values for additional duty cycles can be obtained
from Figure 6.
DUTY CYCLE
(%)
10
20
30
40
50
60
70
80
90
R_PWM (Ω) (Nearest 1% Values)
5kHz
25kHz
100kHz
412k
487k
562k
649k
715k
787k
887k
953k
1050k
84.5k
97.6k
113k
130k
147k
162k
174k
191k
205k
25.5k
28.7k
31.6k
35.7k
39.2k
43.2k
44.9k
—
—
TABLE III. Duty Cycle Adjust Resistance.
10M
DUTY CYCLE vs R_PWM
1M
100k
10k
0
R_PWM (kΩ) = 334.35 + 7.75(%DC)
5kHz
R_PWM (kΩ) = 68.73 + 1.52(%DC)
25kHz
100kHz
R_PWM (kΩ) = 20.62 + 0.39(%DC)
20
40
60
80
100
Duty Cycle (%)
FIGURE 6. Using a Resistor to Program Duty Cycle.
Voltage Controlled Duty Cycle
The duty cycle can also be programmed by analog voltage
V_PWM. With V_PWM ≈ 3.59V, the duty cycle is about 90%.
Decreasing this voltage results in decreased duty cycles. Table
IV provides V_PWM values for typical duty cycles. Figure 7 shows
the relationship of duty cycle versus V_PWM and its linearity.
DUTY CYCLE AND DUTY CYCLE ERROR
vs VOLTAGE
100
2.0
90 ^{At VS = 24V and F = 25kHz: VPWM = 1.25 + 0.026 × %DC} _1.5
80
Duty Cycle ^1.0
70
60
0.5
50
0
40
Duty Cycle Error ^–0.5
30
–1.0
20
10
–1.5
0
–2.0
1
2
3
4
V_PWM (V)
FIGURE 7. Using a Voltage to Program Duty Cycle.
DUTY CYCLE
(%)
10
20
40
60
80
90
TABLE IV. Duty Cycle Adjust Voltage.
V_PWM
(V)
1.501
1.773
2.296
2.813
3.337
3.589
DRV104
9
SBVS036B
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