MCP1630RD-SALED Microchip Technology, MCP1630RD-SALED Datasheet - Page 15

• Manufacturer Part Number: MCP1630RD-SALED
• Description: Power Management IC Development Tools MCP1630 Sepic Automotive LED Drvr
• Manufacturer: Microchip Technology
• Type: DC/DC Converters, Regulators & Controllersr

Specifications of MCP1630RD-SALED

• Rohs: yes
• Product: Reference Designs
• Tool Is For Evaluation Of: MCP1630
• Input Voltage: 9 V to 16 V
• Output Voltage: 55 V
• Output Current: 350 mA

2.3
2.4
© 2011 Microchip Technology Inc.
EVALUATING THE APPLICATION
FIRMWARE DESCRIPTION
2.2.5
When the board is powered up, it supplies the maximum output current (350mA). The
user has the option to adjust this output current connecting an external push button
(see Figure 2-1). The push button controls the output current in eight steps from 0 to
350mA.
The board has Under Voltage Lock-Out and Over Voltage Lock-Out protections. The
thresholds are set in firmware and are 8 V
The board is protected for the No-Load condition. The typical threshold value is 55 V
for the output voltage.
The best way to evaluate the MCP1630 Sepic Automotive LED Driver Reference
Design is to dig into the circuit and measure the voltages and currents with a Digital
Voltage Meter (DVM), and probe the board with an oscilloscope.
Additional tools are necessary to evaluate some technical parameters of the board
(temperature of power components, ability to withstand surge voltage pulse on input,
EMI).
Some typical voltage and waveforms are provided in
Waveforms”.
The firmware program of the PIC12F683 can also be edited to modify the operation of
the application.
The PIC12F683 is preprogrammed with firmware to operate the system, as described
in the previous sections. The firmware flow diagram is shown in
C. “Firmware
The TRISIO register controls the direction of the GPIO pins, and is configured to set
GP2 (oscillator pulses to the MCP1630) and GP5 (V
ports. GP1 and GP4 are configured as analog inputs. These inputs are used to
measure the input and output voltages.
The Capture/Compare/PWM (CCP) block is used to generate the master clock for the
MCP1630 device. This module is configured for PWM mode operation. The PWM
period can be calculated by writing to the PR2 register. The PWM duty cycle is specified
by writing to the CCPR1L register and to the CCP1CON<5:4> bits. A resolution, up to
10-bit, is available. The CCPR1L contains the eight MSbs, while the CCP1CON<5:4>
contains the two LSbs. This 10-bit value is represented by the
CCPR1L:CCP1CON<5:4> bits. The switching frequency is set to 330 kHz.
The reference voltage for the MCP1630 device is produced by the software PWM. This
allows the user to adjust the LED’s intensity in eight steps.
The No-Load condition protection is provided by using the internal comparator. If the
output voltage is too high, an interrupt occurs and the master clock for PWM operation
is disabled.
The internal ADC is used to monitor the input voltage. If the input voltage is too low or
too high, the board will be in a “Power Off” condition.
The Soft Start feature is also provided in this firmware. The duty cycle is gradually
increased until it reaches the maximum value.
Note:
Using the Reference Board
It is not recommended to operate the board without a proper load
connected to the output. The maximum power at the output must be limited
to 19W at ambient temperature.
Flowchart”. The program is simple and straightforward.
Installation and Operation
DC
and 17 V
REF
Appendix D. “Test Points and
DC
voltage to MCP1630) as output
, respectively.
Appendix
DS51955A-page 15
DC