6

Functional description

6.1

Logic inputs

The MASTERGAN1 features a half-bridge gate driver with three logic inputs to control the internal high-side and

low-side GaN transistors.

The devices are controlled through the following logic inputs:

•

SD/OD: Shutdown input, active low;

•

LIN: low-side driver inputs, active high;

•

HIN: high-side driver inputs, active high.

Table 9. Inputs truth table (applicable when device is not in UVLO)

Input pins

GaN transistors status

SD/OD

LIN

HIN

LS

HS

L

X(1)

X(1)

OFF

OFF

H

L

L

OFF

OFF

H

L

H

OFF

ON

H

H

L

ON

OFF

H

H(2)

H(2)

OFF

OFF

1. X: Don’t care

2. Interlocking

The logic inputs have internal pull-down resistors. The purpose of these resistors is to set a proper logic level in

case, for example, there is an interruption in the logic lines or the controller outputs are in tri-state conditions.

If logic inputs are left floating, the gate driver outputs are set to low level and the correspondent GaN transistors

are turned off.

The internal logic is able to transfer the control signal pulse longer than TIN_MIN = 120 ns and introduces a very

short propagation delay to output.

6.2

Bootstrap structure

A bootstrap circuitry is typically used to supply the high-voltage section. MASTERGAN1 integrates this structure,

realized by a patented integrated high-voltage DMOS, to reduce the external components.

The Boostrap integrated circuit is connected to VCC pin and is driven synchronously with the low-side driver.

The use of an external bootstrap diode in parallel to the integrated structure is possible, in particular if the

operating frequency is approximately higher than 500 kHz.

6.3

VCC supply pins and UVLO function

The VCC pin supplies current to the logic circuit, level-shifters in the low-side section and the integrated bootstrap

diode.

The PVCC pin supplies low-side output buffer. During output commutations the average current used to provide

gate charge to the high-side and low-side GaN transistors flows through this pin.

The PVCC pin can be connected either to the same supply voltage of the VCC pin or to a separated voltage

source. In case the same voltage source is used, it is suggested to connect VCC and PVCC pins by means of a

small decoupling resistance. The use of dedicated bypass ceramic capacitors located as close as possible to

each supply pin is highly recommended.

MASTERGAN1

Functional description

DS13417 - Rev 3

page 15/27