Control 5V supplied seven segment led group with 3.3V PIC microcontroller
To block current through Q1, at least emitter voltage should be on it's base. To provide that, R5 is used as pull-up. R4 will drop voltage on Q1 base when Q3 starts to conduct, thus closing Q1. It's not cheapest solution, but easy to build using off-the-shelf components. R4 can be smaller, when more Q1 collector current is nedded. See:



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EDIT
This doesn't meet requirements - lowers voltage to 3v3



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