Datasheet

© 2008-2012 Microchip Technology Inc. DS70318F-page 261
dsPIC33FJ06GS101/X02 and dsPIC33FJ16GSX02/X04
20.0 HIGH-SPEED ANALOG
COMPARATOR
The dsPIC33F SMPS Comparator module monitors
current and/or voltage transients that may be too fast
for the CPU and ADC to capture.
20.1 Features Overview
The SMPS comparator module contains the following
major features:
• 16 selectable comparator inputs
• Up to four analog comparators
• 10-bit DAC for each analog comparator
• Programmable output polarity
• Interrupt generation capability
• DACOUT pin to provide DAC output
• DAC has three ranges of operation:
-AV
DD/2
- Internal Reference (INTREF)
- External Reference (EXTREF)
• ADC sample and convert trigger capability
• Disable capability reduces power consumption
• Functional support for PWM module:
- PWM duty cycle control
- PWM period control
- PWM Fault detect
20.2 Module Description
Figure 20-1 shows a functional block diagram of one
analog comparator from the SMPS comparator
module. The analog comparator provides high-speed
operation with a typical delay of 20 ns. The comparator
has a typical offset voltage of ±5 mV. The negative
input of the comparator is always connected to the
DAC circuit. The positive input of the comparator is
connected to an analog multiplexer that selects the
desired source pin.
The analog comparator input pins are typically shared
with pins used by the Analog-to-Digital Converter
(ADC) module. Both the comparator and the ADC can
use the same pins at the same time. This capability
enables a user to measure an input voltage with the
ADC and detect voltage transients with the
comparator.
FIGURE 20-1: COMPARATOR MODULE BLOCK DIAGRAM
Note 1: This data sheet summarizes the
features of the dsPIC33FJ06GS101/X02
and dsPIC33FJ16GSX02/X04 families
of devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to Section 45. “High-Speed
Analog Comparator” (DS70296) in the
“dsPIC33F/PIC24H Family Reference
Manual”, which is available on the
Microchip web site
(www.microchip.com).
2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
Section 4.0 “Memory Organization” in
this data sheet for device-specific register
and bit information.
CMPxA
(1)
CMPxC
(1)
DAC
CMPPOL
0
1
AVDD/2
INTREF
(2)
M
U
X
M
U
X
CMREF
CMPx
(1)
INSEL<1:0>
10
ACMPx (Trigger to PWM)
(1)
Interrupt Request
CMPxB
(1)
CMPxD
(1)
Glitch Filter
Pulse
EXTREF
(2)
Status
AVSS
Generator
RANGE
DACOUT
DACOE
Note 1: x = 1, 2, 3, and 4.
2: For the INTREF and EXTREF values, refer to the DAC Module Specifications (Table 24-43) in Section 24.0
“Electrical Characteristics”.