MCP1631RD-MCC2 Microchip Technology, MCP1631RD-MCC2 Datasheet - Page 51

• Manufacturer Part Number: MCP1631RD-MCC2
• Description: REFERENCE DESIGN MCP1631HV
• Manufacturer: Microchip Technology

Specifications of MCP1631RD-MCC2

• Main Purpose: Power Management, Battery Charger
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: MCP1631HV, PIC16F883
• Primary Attributes: 1 ~ 2 Cell- Li-Ion, 1 ~ 5 Cell- NiCd/NiMH, 1 ~ 2 1W LEDs
• Secondary Attributes: Status LEDs
• Silicon Manufacturer: Microchip
• Application Sub Type: Battery Charger
• Kit Application Type: Power Management - Battery
• Silicon Core Number: MCP1631HV, PIC16F883
• Kit Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

D.1
© 2009 Microchip Technology Inc.
DESIGN EXAMPLE
D.1.1
• P
• V
• V
• I
• η = Switcher Efficiency @ 80% (typical)
• V
• I
• F
• D
• Choose C20 (Artificial Ramp) = 1500 pF
D.1.2
• Duty Cycle (D) = ((V
• t
• t
• L = V
• ΔI
• ΔI
• I
• P
D.1.3
• M
• τ
= ((8.4V + 0.35)/0.8)/(((8.4V + 0.35)/0.8) + 6V)
= 65% (worst case is two Li-Ion batteries)
For SEPIC coupled inductor, use ½ L because V
L
ΔI
I
= 390 mA * 0.11Ω/1.5 us = 0.0429V/1.5 µs
But the ramp divider is (R10 + R11)/(R10 + R11 + R35)
= (1k + 1k)/(1k + 1k + 20k) = 2k/22k = 1/11
= (0.0429V/1.5 µs)/(1/11) = 471.9 mV/1.5 µs
= -t
= -1.5 µs/(Ln(1 – (0.4719V/5.0V)))
= -1.5 µs/Ln (0.90562) = 15.13 µs
OUT
IN_WC
ON
OFF
IN
IN PEAK
Artificial Ramp
COUPLED
OUT
IN
OUT
F
OSC
OUT
OSC
Artificial Ramp
L
L
IN
= I
= Schottky Diode Drop @ 0.35V (typical)
OFF
= 2 * V
≅ 390 mA
= 6V to 16V for MCP1631HV. Choose V
= D * 1/F
= ΔI
Appendix D. Design Example
= T
= 1.5A for 4 NiMH batteries. Choose DI
IN
OUT
= 500 kHz, T
= 10W (typical)
= 8.4V for two Li-Ion batteries or 6.6V for four NiMH batteries
= V
= 25%, t
/(Ln(1-(V
= I
* D * T
SWITCH
L
= I
Design Parameters:
Design:
Slope Compensation:
OUT
OUT
= 390 mA
* V
IN
= 26 µH/2 = 13 µH. Choose 10 µH as standard value.
IN
SWITCH
* D * T
OUT
(R33 & C20) - Using V
+ ½ ΔI
* I
* V
= ΔI
SWITCH
OSC_ON
- t
OUT
OUT
/(V
OUT_WC
ON
L
SWITCH
SWITCH
/V
IN
* R
L
OUT
= 6.6V * 1.5A = 9.9W
MCP1631HV MULTI-CHEMISTRY
= 0.65/500 kHz = 1.3 µs
= 2 µs – 1.3 µs = 0.7 µs
/ΔI
= 2.06A + 0.195A = 2.26A
IN)
* η)= 1.5A * 6.6V/( 6V * 0.8) = 2.06A
= 0.5 µs, t
SENSE
L
))
+ V
/(V
= 6V * 0.65 * 2 µs/300 mA = 26 µH.
= 1/F
/ (4 * L
F
IN_WC
/t
)/η)/(((V
OSC_FF
SWITCH
OSC_OFF
COUPLED
* ç) = 1.5A * 6.6V/(6V * 0.8) = 2.06A
OUT
OUT
= 2 µs
= V
REFERENCE DESIGN
+ V
= 1.5 µs
BATTERY CHARGER
) = 2*6V*0.65*2 µs/(4*10 µH)
IN
L
IN
F
= 20%, I
)/η) +
= 6V for worst case (WC).
(1-e
IN
“sees” 2 inductors.
-(T/τ)
VIN
OUT
)
)
= 300 mA.
DS51791A-page 47