ALM2403-Q1
ZHCSMT3A –NOVEMBER 2020 –REVISED MARCH 2023
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Resolver excitation coils can have a very low dc resistance (< 100 Ω), requiring a sink and a source of up to 200
mA from the excitation driver. The ALM2403-Q1 can source and sink this current while providing current-limiting
and thermal-shutdown protection. Incorporating these protections in a resolver design can increase the life of the
end product.
The input to the ALM2403-Q1 can be an analog sine wave generated by the resolver-to-digital converter chip or
a pulse-width modulation (PWM) signal generated from a microcontroller I/O pin. In the case of the latter, a filter
stage is needed to extract a lower bandwidth sine wave from the PWM signal. This sine wave would then be the
input signal to the ALM2403-Q1. As a result of high gain bandwidth, the ALM2403-Q1 can be configured as a
filter stage while providing the required output drive. This configuration significantly reduces the total solution
size and design complexity of the resolver-drive signal chain. The fundamental design steps to achieve this
functionality are shown in this application example, and can be applied to other inductive-load applications as
well.
R2
C3
R1
R3
VOUT1
C1
œ
C2
PWM input
+
VBIAS
ALM2403-Q1 channel 1
CEMC
Sin
C4
R5
CEMC
Cos
Resolver
VOUT1
R4
œ
+
VBIAS
ALM2403-Q1 channel 2
图8-2. Resolver-Based Application
8.2.1 Design Requirements
For this design example, use the parameters listed in 表8-1 as the input parameters.
表8-1. Design Parameters
DESIGN PARAMETER
Ambient temperature range
Available supply voltages
EMC capacitance (CL)
EXAMPLE VALUE
–40°C to +125°C
15 V
10 nF
Resolver excitation input voltage
Excitation frequency
7 VRMS
10 kHz
PWM signal frequency
320 kHz
3.3 V
PWM signal amplitude
Functional safety capable
Short-to-battery protection
Yes
Yes
Copyright © 2023 Texas Instruments Incorporated
English Data Sheet: SBOSA37
16
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