MICROCHIP HV9930LG-G

The HV9930 is a variable frequency PWM controller IC designed to control an LED lamp driver using a low-noise boost-buck (Cuk) topology. The HV9930 uses a patented Hysteretic Current-mode control to regulate both the input and output currents. This enables superior input surge immunity without the necessity for complex loop compensation. Input current control enables current limiting during Startup, Input Undervoltage, and Output Overload conditions. The HV9930 provides a low-frequency PWM dimming input that can accept an external control signal with a duty cycle of 0% to 100% and a high dimming ratio. The HV9930-based LED driver is ideal for LED lamps and RGB backlight applications with low-voltage DC inputs. The HV9930-based LED Lamp drivers can achieve efficiency in excess of 80%.

The HV9930 is optimized to drive a Continuous Conduction Mode (CCM) boost-buck DC/DC converter topology commonly referred to as Cuk converter. This power converter topology offers numerous advantages useful for driving high-brightness light-emitting diodes (HB LED). These advantages include step-up or step-down voltage conversion ratio and low input and output current ripple. The input and output inductors can also share a common core to achieve ripple current cancellation. The output load is decoupled from the input voltage with a capacitor, making the driver inherently failure-safe for the output load. The HV9930 offers a simple and effective control technique for a boost-buck LED driver. It uses two Hysteretic mode controllers—one for the input and one for the output. The outputs of these two hysteretic comparators are logically being AND together and are used to drive the external FET. This control scheme gives accurate current control and constant output current in the presence of input voltage transients without the need for complicated loop design.

The HV9930 can be powered directly from its V_IN pin that takes voltage from 8V up to the maximum of 200V. When voltage is applied to the V_IN pin, the HV9930 attempts to regulate a constant 7.5V (typical) at the V_DD pin. The regulator also has a built-in undervoltage lockout which shuts off the IC when the voltage at the V_DD pin falls below the UVLO lower threshold. The V_DD pin must be bypassed by a low-ESR capacitor (≥0.1 HF) to provide a low-impedance path for the high-frequency current of the output gate driver. The IC can also be operated by supplying a voltage at the V_DD pin greater than the internally regulated voltage. This will turn off the internal linear regulator and the IC will function by drawing power from the external voltage source connected to the V_DD pin. In case of input transients that reduce the input voltage below 8V (e.g. Cold Crank condition in an automotive system), the V_IN pin of the HV9930 can be connected to the external MOSFET drain through a diode. Since the drain of the FET is at a voltage equal to the sum of the input and output voltages, the IC will still be operational when the input goes below 8V. In these cases, a larger capacitor is needed for the V_DD pin to supply power to the IC when the MOSFET switches on.

An internally trimmed voltage reference of 1.25V (± 3%) is provided at the REF pin. The reference can supply a maximum output current of 1 mA to drive external circuitry. This reference can be used to set the current-sense

• Constant Output Current LED Driver
• Steps Output Voltage Up or Down
• Low EMI
• Variable Frequency Operation
• Internal 8V to 200V Linear Regulator
• Input and Output Current Sensing
• Input Current Limit
• Enable and Pulse-Width Modulation (PWM) Dimming

• RGB Backlight Applications
• Battery-Powered LED Lamps
• Other Low-Voltage AC/DC or DC/DC LED Drivers