AN3400 Datasheet, PDF (48/78 Pages) STMicroelectronics – Analysis and simulation of a BJT complementary pair in a self-oscillating CFL solution

Modeling of the re-circulating phase preliminary to the PNP conduction time phase
AN3400
Figure 27. Driving network modeling for the simulation of the second re-circulating phase
preliminary to the PNP bipolar conduction time phase
VRs
IRs
Rs
VCn
ICn
Cn
VRs
IRs
Rs
VCn
ICn
Cn
Is2
Rb
VRb
IRb
VEBp
ILP
Lp
IE2
Is2
Rb
VRb
ILP
IRb
IE2
VEBp
Cp
ICp
VCp
Q2
IBp
VCBp
IC2
GND
Cp
ICp
VCp
IBp
VCBp
IC2
GND
AM09817v1
Equations in the System of equations 6 and System of equations 7, describing the working
conditions of the PNP bipolar during the re-circulating phase before the PNP bipolar
conduction time, can be combined, with each other, in order to obtain the following system
of two first order linear differential equations valid on all the [t₆,t₈] time interval with
C=C_n=C_p:
System of equations 20
( ( )) ^d
dt
V_{Cn−pnpric}
t
=− ¹
C ⋅R_b
⋅ V_{Cn−pnpric}
−¹
C ⋅ R_b
⋅ V_{Cp−pnpric}
( ( )) ^d
dt ^{VCp−pnpric t}
=
−¹
C ⋅ R_b
⋅ V_{Cn−pnpric}
−
1
C ⋅ R_b
⋅ V_{Cp−pnpric}
+ ^IS
C
( ) ( ) V_{Cn−pnpric} t₆₊ = V_{Cn−npndead} t_6−
( ) ( ) V_{Cp−pnpric} t ₆₊ = V_{Cp−npndead} t_6−
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Doc ID 018840 Rev 1