High Performance Dual Channel Current Mode Controllers

The MC34065−H,L series are high performance, fixed frequency, dual current mode controllers. They are specifically designed for off−line and dc−to−dc converter applications offering the designer a cost effective solution with minimal external components. These integrated circuits feature a unique oscillator for precise duty cycle limit and frequency control, a temperature compensated reference, two high gain error amplifiers, two current sensing comparators, Drive Output 2 Enable pin, and two high current totem pole outputs ideally suited for driving power MOSFETs.

Also included are protective features consisting of input and reference undervoltage lockouts each with hysteresis, cycle−by−cycle current limiting, and a latch for single pulse metering of each output. These devices are available in dual−in−line and surface mount packages.

The MC34065−H has UVLO thresholds of 14 V (on) and 10 V (off), ideally suited for off−line converters. The MC34065−L is tailored for lower voltage applications having UVLO thresholds of 8.4 V (on) and 7.8 V (off).

• Unique Oscillator for Precise Duty Cycle Limit and Frequency Control

• Current Mode Operation to 500 kHz

• Automatic Feed Forward Compensation

• Separate Latching PWMs for Cycle−By−Cycle Current Limiting

• Internally Trimmed Reference with Undervoltage Lockout

• Drive Output 2 Enable Pin

• Two High Current Totem Pole Outputs

• Input Undervoltage Lockout with Hysteresis

• Low Startup and Operating Current