UC3860N Datasheet, PDF (1/10 Pages) Texas Instruments – Resonant Mode Power Supply Controller

Resonant Mode Power Supply Controller
UC1860
UC2860
UC3860
FEATURES
• 3MHz VFO Linear over 100:1 Range
• 5MHz Error Amplifier with Controlled
Output Swing
• Programmable One Shot Timer—
Down to 100ns
• Precision 5V Reference
• Dual 2A Peak Totem Pole Outputs
• Programmable Output Sequence
• Programmable Under Voltage Lockout
• Very Low Start Up Current
• Programmable Fault Management &
Restart Delay
• Uncommitted Comparator
DESCRIPTION
The UC1860 family of control ICs is a versatile system for resonant mode
power supply control. This device easily implements frequency modulated
fixed-on-time control schemes as well as a number of other power supply
control schemes with its various dedicated and programmable features.
The UC1860 includes a precision voltage reference, a wide-bandwidth er-
ror amplifier, a variable frequency oscillator operable to beyond 3MHz, an
oscillator-triggered one-shot, dual high-current totem-pole output drivers,
and a programmable toggle flip-flop. The output mode is easily pro-
grammed for various sequences such as A, off, B, off; A & B, off; or A, B,
off. The error amplifier contains precision output clamps that allow pro-
gramming of minimum and maximum frequency.
The device also contains an uncommitted comparator, a fast comparator
for fault sensing, programmable soft start circuitry, and a programmable
restart delay. Hic-up style response to faults is easily achieved. In addi-
tion, the UC1860 contains programmable under voltage lockout circuitry
that forces the output stages low and minimizes supply current during
start-up conditions.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (pin 19) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V
Output Current, Source or Sink (pins 17 & 20)
DC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.8A
Pulse (0.5µs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0A
Power Ground Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±0.2V
Inputs (pins 1, 2, 3, 4, 8, 9, 11, 12,
13, 14, 21, 22, 23 & 24) . . . . . . . . . . . . . . . . . . . . . . -0.4 to 6V
Error Amp Output Current, Source or Sink (pin 5) . . . . . . . . 2mA
IVFO Current (pin 7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2mA
Comparator Output Current (pin 15) . . . . . . . . . . . . . . . . . . 5mA
Comparator Output Voltage (pin 15) . . . . . . . . . . . . . . . . . . 15V
Soft Start or Restart Delay Sink Current (pins 22 & 23) . . . 5mA
Power Dissipation at TA = 50°C (DIP) . . . . . . . . . . . . . . . 1.25W
Power Dissipation at TA = 50°C (PLCC) . . . . . . . . . . . . . . . . 1W
Lead Temperature (Soldering, 10 seconds) . . . . . . . . . . . 300°C
Note: All voltages are with respect to signal ground and all
currents are positive into the specified terminal.
Pin numbers refer to the DIP.
Refer to Packaging Section of Databook for thermal
limitations and considerations of packages.
BLOCK DIAGRAM
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