PIC18F86K90-I/PT Microchip Technology, PIC18F86K90-I/PT Datasheet - Page 265

• Manufacturer Part Number: PIC18F86K90-I/PT
• Description: 64kB Flash, 4kB RAM, 1kB EE, 16MIPS, NanoWatt XLP, LCD, 5V 80 TQFP 12x12x1mm TRA
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F86K90-I/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 64MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 69
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 24x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TQFP
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

19.4.6
In half-bridge applications, where all power switches
are modulated at the PWM frequency, the power
switches normally require more time to turn off than to
turn on. If both the upper and lower power switches are
switched at the same time (one turned on and the other
turned off), both switches may be on for a short period
until one switch completely turns off. During this brief
interval, a very high current (shoot-through current) will
flow through both power switches, shorting the bridge
supply.
shoot-through current from flowing during switching,
turning on either of the power switches is normally
delayed to allow the other switch to completely turn off.
In Half-Bridge mode, a digitally programmable
dead-band delay is available to avoid shoot-through
current from destroying the bridge power switches. The
delay occurs at the signal transition from the non-active
state to the active state. For an illustration, see
Figure 19-14. The lower seven bits of the associated
ECCPxDEL register (Register 19-4) set the delay
period in terms of microcontroller instruction cycles
(T
FIGURE 19-15:
 2010 Microchip Technology Inc.
CY
or 4 T
Standard Half-Bridge Circuit (“Push-Pull”)
To
OSC
PROGRAMMABLE DEAD-BAND
DELAY MODE
).
avoid
EXAMPLE OF HALF-BRIDGE APPLICATIONS
this
potentially
PxA
PxB
destructive
Preliminary
FET
Driver
FET
Driver
PIC18F87K90 FAMILY
FIGURE 19-14:
PxA
PxB
td = Dead-Band Delay
Note 1: At this time, the TMR2 register is equal to the
(2)
(2)
V+
V-
2: Output signals are shown as active-high.
(1)
Pulse Width
PR2 register.
td
Load
Period
td
EXAMPLE OF
HALF-BRIDGE PWM
OUTPUT
+
V
-
+
V
-
(1)
DS39957B-page 265
Period
(1)