摘要:
A current-mirror arrangement comprises a first and a second transistor whose bases are interconnected and connected to the collector of the first transistor. The transistors are constructed as vertical transistors each having a collector region (23a, 23b) of a first conductivity type, isolated from a substrate (21) of the first conductivity type by an intermediate layer (22) of a second conductivity type, a connection being provided between said intermediate layer (22) and the interconnected bases (29, 30) of the two transistors.
摘要:
A first amplifier (A1) and a second amplifier (A2) are protected against short-circuits by a protection device comprising first means (M1), second means (M2), third means (M3) and protection means (B). For this purpose the first means (M1) and the second means (M2) generate four signals (s1, s2, s3, s4) related to an equal number of currents (i1, i2, i3, i4), which contribute to a first or a second load current in the first amplifier (A1) or in the second amplifier (A2). For controlling the protection means (B) the third means (M3) generate at least two control signals (r1, r2) related to the signals (s1, s2, s3, s4), use being made of the equality of the load currents in the absence of short-circuits.
摘要:
In order to boost the output power of a first amplifier (A1) a second amplifier (A2) can increase the supply voltage difference across the first amplifier (A1). However, variations of the supply voltage difference are attended with a comparatively high distortion. In order to minimize this distortion while maintaining the output power a signal-follower circuit (M1, M2, S) generates a direct voltage level of which tracks a first output signal (Vuit1) of the first amplifier (A1), for which purpose the signal-follower circuit (M1, M2, S) is driven by a third amplifier (A3), which compares the first output signal (Vuit1) with a reference signal (Vref).
摘要:
The first (T₁) and the second (T₂) output transistor of an amplifier arrangement are push-pull driven by means of a drive circuit (10) having two transistors (T₁₁, T₁₂) which are each loaded by a current source (T₁₃, T₁₄). Currents which are a measure of the currents flowing through the first (T₁) and the second (T₂) output transistor are generated by a first (20) and second (30) current measuring means. These currents are applied to a negative feedback means (40) which controls the current intensity of the current sources (T₁₃, T₁₄) in such a way that the harmonic mean value of the currents flowing through the first (T₁) and the second (T₂) output transistor is substantially equal to a reference value.