PIC16C781-I/P Microchip Technology, PIC16C781-I/P Datasheet - Page 109

• Manufacturer Part Number: PIC16C781-I/P
• Description: IC MCU OTP 1KX14 W/AD COMP 20DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Cr

Specifications of PIC16C781-I/P

• Core Size: 8-Bit
• Program Memory Size: 1.75KB (1K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 13
• Program Memory Type: OTP
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x8b; D/A 1x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-DIP (0.300", 7.62mm)
• Controller Family/series: PIC16C
• No. Of I/o's: 16
• Ram Memory Size: 128Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Processor Series: PIC16C
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 16
• Number Of Timers: 2
• Operating Supply Voltage: 2.5 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: ICE2000, DM163022
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• On-chip Dac: 8 bit, 1 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: ISPICR1 - ADAPTER IN-CIRCUIT PROGRAMMINGDVA16XP202 - ADAPTER DEVICE PIC16C781/782DM163012 - BOARD DEMO PICDEM FOR 16C781/782AC164028 - MODULE SKT PROMATEII 20SOIC/DIP
• Eeprom Size: -
• Connectivity: -
• Lead Free Status / Rohs Status: Details
• Other names: PIC16C781I/P

13.3
The programmable nature of the PSMC lends itself to a
wide variety of applications involving current or voltage
management. The following examples are intended to
provide suggested applications for the PSMC. The
examples are not complete designs, but rather block
diagrams of some potential applications of the PSMC.
For a broader list of applications, including supporting
math and firmware examples, please refer to Microchip
web page for applicable Application Notes.
13.3.1
In this example, the PSMC controls the boost configu-
ration switching power supply in Figure 13-5.
The PSMC is configured as a two feedback loop PWM,
current mode, switching power supply controller. The
inner current feedback loops consist of:
• PSMC
• MOSFET driver
• Power MOSFET Q1
• Inductor L1
• Current transformer
• Comparator C1
The outer voltage feedback loop consists of:
• Diode D1
• C
• OPAMP feedback filter
• DAC reference
2001 Microchip Technology Inc.
MAIN
Configuration
EXAMPLE BOOST LC SWITCHING
POWER SUPPLY
Preliminary
The inner current loop is a pulsed current source driven
by the PSMC. During the active phase of the output
pulse, the inner loop builds up a current flow in inductor
L1. The current in L1 is monitored by the current trans-
former. The output of the transformer is offset by the
ramp from the slope compensation network R3/C1 and
then fed into the comparator. When the voltage (pro-
portional to the current flow in L1, offset by the slope
compensation) exceeds the error voltage from the
OPAMP, Q1 is turned off and L1 discharges through D1
into C
The outer voltage loop monitors the output voltage
across C
the DAC is subtracted, generating the raw error volt-
age. The raw error voltage is filtered by the OPAMP
and routed to Comparator C1 in the inner current loop.
The phase compensation output of the PSMC acts to
improve loop stability by adding a pseudo-ramp wave-
form to the current sense transformer feedback in the
inner loop. In conditions where the charge phase of the
cycle is greater then 50%, the increased current feed-
back reduces the current charge in L1, slowing the
charging of C
all loop gain for duty cycles of >50%, maintaining loop
stability.
MAIN
MAIN
for the remainder of the period.
MAIN
using R1/R2. The reference voltage from
PIC16C781/782
. The result is a reduction in the over-
DS41171A-page 107